C2 domain present in Arf GTPase Activating Proteins (GAP); ArfGAP is a GTPase activating protein which regulates the ADP ribosylation factor Arf, a member of the Ras superfamily of GTP-binding proteins. The GTP-bound form of Arf is involved in Golgi morphology and is involved in recruiting coat proteins. ArfGAP is responsible for the GDP-bound form of Arf which is necessary for uncoating the membrane and allowing the Golgi to fuse with an acceptor compartment. These proteins contain an N-terminal ArfGAP domain containing the characteristic zinc finger motif (Cys-x2-Cys-x(16,17)-x2-Cys) and C-terminal C2 domain. C2 domains were first identified in Protein Kinase C (PKC). C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 144 IGLLKVTIKKGTNLAIRDMMSSDPYVVLNLGKQKLQTTVMNSNLNPVWNQELMLSVPESYGPVKLQVYDYDTFSADDIMG 223
Cdd:cd04038     1 LGLLKVRVVRGTNLAVRDFTSSDPYVVLTLGNQKVKTRVIKKNLNPVWNEELTLSVPNPMAPLKLEVFDKDTFSKDDSMG 80

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1063721150 224 EADIDIQPLITSAMAFGDPEMFGDMQIGKWLKSHDNPLIDDSIINIVDGKVKQEVQIKLQNVESG 288
Cdd:cd04038    81 EAEIDLEPLVEAAKLDHLRDTPGGTQIKKVLPSVENCLASESHITWKDGKIVQDLVLKLRNVESG 145

C2 domain present in Arf GTPase Activating Proteins (GAP); ArfGAP is a GTPase activating protein which regulates the ADP ribosylation factor Arf, a member of the Ras superfamily of GTP-binding proteins. The GTP-bound form of Arf is involved in Golgi morphology and is involved in recruiting coat proteins. ArfGAP is responsible for the GDP-bound form of Arf which is necessary for uncoating the membrane and allowing the Golgi to fuse with an acceptor compartment. These proteins contain an N-terminal ArfGAP domain containing the characteristic zinc finger motif (Cys-x2-Cys-x(16,17)-x2-Cys) and C-terminal C2 domain. C2 domains were first identified in Protein Kinase C (PKC). C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 144 IGLLKVTIKKGTNLAIRDMMSSDPYVVLNLGKQKLQTTVMNSNLNPVWNQELMLSVPESYGPVKLQVYDYDTFSADDIMG 223
Cdd:cd04038     1 LGLLKVRVVRGTNLAVRDFTSSDPYVVLTLGNQKVKTRVIKKNLNPVWNEELTLSVPNPMAPLKLEVFDKDTFSKDDSMG 80

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1063721150 224 EADIDIQPLITSAMAFGDPEMFGDMQIGKWLKSHDNPLIDDSIINIVDGKVKQEVQIKLQNVESG 288
Cdd:cd04038    81 EAEIDLEPLVEAAKLDHLRDTPGGTQIKKVLPSVENCLASESHITWKDGKIVQDLVLKLRNVESG 145

Putative GTPase activating protein for Arf; Putative zinc fingers with GTPase activating proteins (GAPs) towards the small GTPase, Arf. The GAP of ARD1 stimulates GTPase hydrolysis for ARD1 but not ARFs.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEiGGNASANSIYEAFLPDtCSKPGPDVNHDQRMRFIR 86
Cdd:pfam01412  28 SVNLGIFICIDCSGVHRSLGVHISKVRSLTLDTWTDEQLELMKA-GGNDRANEFWEANLPP-SYKPPPSSDREKRESFIR 105

                          90
                  ....*....|..
gi 1063721150  87 AKYELQEFLKPS 98
Cdd:pfam01412 106 AKYVEKKFAKPG 117

C2 domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 145 GLLKVTIKKGTNLAIRDMM-SSDPYVVLNL--GKQKLQTTVMNSNLNPVWNQELMLSVPESYG-PVKLQVYDYDTFSADD 220
Cdd:pfam00168   1 GRLTVTVIEAKNLPPKDGNgTSDPYVKVYLldGKQKKKTKVVKNTLNPVWNETFTFSVPDPENaVLEIEVYDYDRFGRDD 80

                          90
                  ....*....|....*
gi 1063721150 221 IMGEADIDIQPLITS 235
Cdd:pfam00168  81 FIGEVRIPLSELDSG 95

Protein kinase C conserved region 2 (CalB); Ca2+-binding motif present in phospholipases, protein kinases C, and synaptotagmins (among others). Some do not appear to contain Ca2+-binding sites. Particular C2s appear to bind phospholipids, inositol polyphosphates, and intracellular proteins. Unusual occurrence in perforin. Synaptotagmin and PLC C2s are permuted in sequence with respect to N- and C-terminal beta strands. SMART detects C2 domains using one or both of two profiles.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150  146 LLKVTIKKGTNLAIRDMM-SSDPYVVLNLG---KQKLQTTVMNSNLNPVWNQELMLSVPESYG-PVKLQVYDYDTFSADD 220
Cdd:smart00239   1 TLTVKIISARNLPPKDKGgKSDPYVKVSLDgdpKEKKKTKVVKNTLNPVWNETFEFEVPPPELaELEIEVYDKDRFGRDD 80

                           90
                   ....*....|....*
gi 1063721150  221 IMGEADIDIQPLITS 235
Cdd:smart00239  81 FIGQVTIPLSDLLLG 95

ADP-ribosylation factor GTPase-activating protein AGD10; Provisional

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIeIGGNASANSIYEAF 64
Cdd:PLN03114   37 SVTYGIFLCIDCSAVHRSLGVHISFVRSTNLDSWSSEQLKMMI-YGGNNRAQVFFKQY 93

C2 domain present in Arf GTPase Activating Proteins (GAP); ArfGAP is a GTPase activating protein which regulates the ADP ribosylation factor Arf, a member of the Ras superfamily of GTP-binding proteins. The GTP-bound form of Arf is involved in Golgi morphology and is involved in recruiting coat proteins. ArfGAP is responsible for the GDP-bound form of Arf which is necessary for uncoating the membrane and allowing the Golgi to fuse with an acceptor compartment. These proteins contain an N-terminal ArfGAP domain containing the characteristic zinc finger motif (Cys-x2-Cys-x(16,17)-x2-Cys) and C-terminal C2 domain. C2 domains were first identified in Protein Kinase C (PKC). C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 144 IGLLKVTIKKGTNLAIRDMMSSDPYVVLNLGKQKLQTTVMNSNLNPVWNQELMLSVPESYGPVKLQVYDYDTFSADDIMG 223
Cdd:cd04038     1 LGLLKVRVVRGTNLAVRDFTSSDPYVVLTLGNQKVKTRVIKKNLNPVWNEELTLSVPNPMAPLKLEVFDKDTFSKDDSMG 80

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1063721150 224 EADIDIQPLITSAMAFGDPEMFGDMQIGKWLKSHDNPLIDDSIINIVDGKVKQEVQIKLQNVESG 288
Cdd:cd04038    81 EAEIDLEPLVEAAKLDHLRDTPGGTQIKKVLPSVENCLASESHITWKDGKIVQDLVLKLRNVESG 145

Putative GTPase activating protein for Arf; Putative zinc fingers with GTPase activating proteins (GAPs) towards the small GTPase, Arf. The GAP of ARD1 stimulates GTPase hydrolysis for ARD1 but not ARFs.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEiGGNASANSIYEAFLPDtCSKPGPDVNHDQRMRFIR 86
Cdd:pfam01412  28 SVNLGIFICIDCSGVHRSLGVHISKVRSLTLDTWTDEQLELMKA-GGNDRANEFWEANLPP-SYKPPPSSDREKRESFIR 105

                          90
                  ....*....|..
gi 1063721150  87 AKYELQEFLKPS 98
Cdd:pfam01412 106 AKYVEKKFAKPG 117

ArfGap with dual PH domains; The ADAP subfamily, ArfGAPs with dual pleckstrin homology (PH) domains, includes two members: ADAP1 and ADAP2. Both ADAP1 (also known as centaurin-alpha1, p42(IP4), or PIP3BP) and ADAP2 (centaurin-alpha2) display a GTPase-activating protein (GAP) activity toward Arf6 (ADP-ribosylation factor 6), which is involved in protein trafficking that regulates endocytic recycling, cytoskeleton remodeling, and neuronal differentiation. ADAP2 has high sequence similarity to the ADAP1 and they both contain a ArfGAP domain at the N-terminus, followed by two PH domains. However, ADAP1, unlike ADAP2, contains a putative N-terminal nuclear localization signal. The PH domains of ADAP1bind to the two second messenger molecules phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) and inositol 1,3,4,5-tetrakisphosphate (I(1,3,4,5)P4) with identical high affinity, whereas those of ADAP2 specifically binds phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) and PI(3,4,5)P3, which are produced by activated phosphatidylinositol 3-kinase. ADAP1 is predominantly expressed in the brain neurons, while ADAP2 is broadly expressed, including the adipocytes, heart, and skeletal muscle but not in the brain. The limited distribution and high expression of ADAP1 in the brain indicates that ADAP1 is important for neuronal functions. ADAP1 has been shown to highly expressed in the neurons and plagues of Alzheimer's disease patients. In other hand, ADAP2 gene deletion has been shown to cause circulatory deficiencies and heart shape defects in zebrafish, indicating that ADAP2 has a vital role in heart development. Taken together, the hemizygous deletion of ADAP2 gene may be contributing to the cardiovascular malformation in patients with neurofibromatosis type 1 (NF1) microdeletions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLPDTCSKPGPDVNHDQRMRFIR 86
Cdd:cd08832    32 SYNLGVFICLDCSGIHRSLGTHISKVKSLRLDNWDDSQVEFMEEN-GNEKAKAKYEAHVPAFYRRPTPTDPQVLREQWIR 110

                  ...
gi 1063721150  87 AKY 89
Cdd:cd08832   111 AKY 113

ArfGAP with GTPase domain, ANK repeat and PH domains; The AGAP subfamily of ADP-ribosylation factor GTPase-activating proteins (Arf GAPs) includes three members: AGAP1-3. In addition to the Arf GAP domain, AGAP proteins contain GTP-binding protein-like, ANK repeat and pleckstrin homology (PH) domains. AGAP1 and AGAP2 have phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2)-mediated GTPase-activating protein (GAP) activity preferentially toward Arf1, and function in the endocytic system. AGAP1 and AGAP2 independently regulate AP-3 endosomes and AP-1/Rab4 fast recycling endosomes, respectively. AGAP1, via its PH domain, directly interacts with the adapter protein 3 (AP-3), which is a coat protein involved in trafficking in the endosomal-lysosomal system, and regulates AP-3-dependent trafficking. In other hand, AGAP2 specifically binds the clathrin adaptor protein AP-1 and regulates the AP-1/Rab-4 dependent endosomal trafficking. AGAP2 is overexpressed in different human cancers including prostate carcinoma and glioblastoma, and promotes cancer cell invasion. AGAP3 exists as a component of the NMDA receptor complex that regulates Arf6 and Ras/ERK signaling pathways. Moreover, AGAP3 regulates AMPA receptor trafficking through the ArfGAP domain. Together, AGAP3 is believed to involve in linking NMDA receptor activation to AMPA receptor trafficking.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLPDtCSKPGPDVNHDQRMRFIR 86
Cdd:cd08836    27 SLNLGALMCIECSGIHRNLGTHISRVRSLDLDDWPVELLKVMSAI-GNDLANSVWEGNTQG-RTKPTPDSSREEKERWIR 104

                  ....
gi 1063721150  87 AKYE 90
Cdd:cd08836   105 AKYE 108

Stromal membrane-associated protein 2; a subfamily of the ArfGAP family; The SMAP subfamily of Arf GTPase-activating proteins consists of the two structurally-related members, SMAP1 and SMAP2. Each SMAP member exhibits common and distinct functions in vesicle trafficking. They both bind to clathrin heavy chain molecules and are involved in the trafficking of clathrin-coated vesicles. SMAP1 preferentially exhibits GAP toward Arf6, while SMAP2 prefers Arf1 as a substrate. SMAP1 is involved in Arf6-dependent vesicle trafficking, but not Arf6-mediated actin cytoskeleton reorganization, and regulates clathrin-dependent endocytosis of the transferrin receptors and E-cadherin. SMAP2 regulates Arf1-dependent retrograde transport of TGN38/46 from the early endosome to the trans-Golgi network (TGN). SMAP2 has the Clathrin Assembly Lymphoid Myeloid (CALM)-binding domain, but SMAP1 does not.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLPDTCSKPgpdvNHDQRMR-FI 85
Cdd:cd08859    25 SWNIGVFICIRCAGIHRNLGVHISRVKSVNLDQWTQEQIQCMQEM-GNGKANRLYEAFLPENFRRP----QTDQAVEgFI 99

                  ....*
gi 1063721150  86 RAKYE 90
Cdd:cd08859   100 RDKYE 104

ArfGAP domain of ASAP (Arf GAP, SH3, ANK repeat and PH domains) subfamily of ADP-ribosylation factor GTPase-activating proteins; The ArfGAPs are a family of multidomain proteins with a common catalytic domain that promotes the hydrolysis of GTP bound to Arf, thereby inactivating Arf signaling. ASAP-subfamily GAPs include three members: ASAP1, ASAP2, ASAP3. The ASAP subfamily comprises Arf GAP, SH3, ANK repeat and PH domains. From the N-terminus, each member has a BAR, PH, Arf GAP, ANK repeat, and proline rich domains. Unlike ASAP3, ASAP1 and ASAP2 also have an SH3 domain at the C-terminus. ASAP1 and ASAP2 show strong GTPase-activating protein (GAP) activity toward Arf1 and Arf5 and weak activity toward Arf6. ASAP1 is a target of Src and FAK signaling that regulates focal adhesions, circular dorsal ruffles (CDR), invadopodia, and podosomes. ASAP1 GAP activity is synergistically stimulated by phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidic acid. ASAP2 is believed to function as an ArfGAP that controls ARF-mediated vesicle budding when recruited to Golgi membranes. It also functions as a substrate and downstream target for protein tyrosine kinases Pyk2 and Src, a pathway that may be involved in the regulation of vesicular transport. ASAP3 is a focal adhesion-associated ArfGAP that functions in cell migration and invasion. Similar to ASAP1, the GAP activity of ASAP3 is strongly enhanced by PIP2 via PH domain. Like ASAP1, ASAP3 associates with focal adhesions and circular dorsal ruffles. However, unlike ASAP1, ASAP3 does not localize to invadopodia or podosomes. Both ASAP 1 and 3 have been implicated in oncogenesis, as ASAP1 is highly expressed in metastatic breast cancer and ASAP3 in hepatocellular carcinoma.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEV---DSMieigGNASANSIYEAFLPDTcSKPGPDVNHDQRMR 83
Cdd:cd08834    30 STNLGILTCIECSGVHRELGVHVSRIQSLTLDNLGTSELllaRNL----GNEGFNEIMEANLPPG-YKPTPNSDMEERKD 104

                  ....*.
gi 1063721150  84 FIRAKY 89
Cdd:cd08834   105 FIRAKY 110

ArfGAP with GTPase domain, ANK repeat and PH domain 3; The AGAP subfamily of ADP-ribosylation factor GTPase-activating proteins (Arf GAPs) includes three members: AGAP1-3. In addition to the Arf GAP domain, AGAP proteins contain GTP-binding protein-like, ANK repeat and pleckstrin homology (PH) domains. AGAP3 exists as a component of the NMDA receptor complex that regulates Arf6 and Ras/ERK signaling pathways. Moreover, AGAP3 regulates AMPA receptor trafficking through the ArfGAP domain. Together, AGAP3 is believed to involve in linking NMDA receptor activation to AMPA receptor trafficking. AGAP1 and AGAP2 have phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2)-mediated GTPase-activating protein (GAP) activity preferentially toward Arf1, and function in the endocytic system. AGAP1 and AGAP2 independently regulate AP-3 endosomes and AP-1/Rab4 fast recycling endosomes, respectively. AGAP1, via its PH domain, directly interacts with the adapter protein 3 (AP-3), which is a coat protein involved in trafficking in the endosomal-lysosomal system, and regulates AP-3-dependent trafficking. In other hand, AGAP2 specifically binds the clathrin adaptor protein AP-1 and regulates the AP-1/Rab-4 dependent endosomal trafficking. AGAP2 is overexpressed in different human cancers including prostate carcinoma and glioblastoma, and promotes cancer cell invasion.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLpDTCSKPGPDVNHDQRMRFIR 86
Cdd:cd08855    29 SLNLGALMCIECSGIHRNLGTHLSRVRSLDLDDWPVELSMVMTAI-GNAMANSVWEGAL-DGYSKPGPDSTREEKERWIR 106

                  ....
gi 1063721150  87 AKYE 90
Cdd:cd08855   107 AKYE 110

ArfGAP domain of ACAP1 (ArfGAP with Coiled-coil, ANK repeat and PH domains 1); ACAP1 belongs to the ACAP subfamily of GAPs (GTPase-activating proteins) for the small GTPase Arf (ADP-ribosylation factor). ACAP subfamily of ArfGAPs are composed of Coiled coli (BAR, Bin-Amphiphysin-Rvs), PH, ArfGAP and ANK repeats domains. ACAP1 (centaurin beta1) and ACAP2 centaurin beta2) have a GAP (GTPase-activating protein) activity preferentially toward Arf6, which regulates endocytic recycling. Both ACAP1/2 are activated by are activated by the phosphoinositides, PI(4,5)P2 and PI(3,5)P2. ACAP1 binds specifically with recycling cargo proteins such as transferrin receptor (TfR) and cellubrevin. Thus, ACAP1 promotes cargo sorting to enhance TfR recycling from the recycling endosome. In addition, phosphorylation of ACAP by Akt, a serine/threonine protein kinase, regulates the recycling of integrin beta1 to control cell migration. In contrast, ACAP2 does not exhibit a similar interaction with the recycling cargo proteins. It has been shown that ACAP2 functions both as an effector of Ras-related protein Rab35 and as an Arf6-GTPase-activating protein (GAP) during neurite outgrowth of PC12 cells. Moreover, ACAP2, together with Rab35, regulates phagocytosis in mammalian macrophages. ACAP3 also positively regulates neurite outgrowth through its GAP activity specific to Arf6 in mouse hippocampal neurons.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLPD-TCSKPGPDVNHDQRMRFI 85
Cdd:cd08852    28 SINLGVTLCIQCSGIHRSLGVHFSKVRSLTLDSWEPELVKLMCEL-GNVIINQIYEARIEAmAIKKPGPSSSRQEKEAWI 106

                          90
                  ....*....|
gi 1063721150  86 RAKYELQEFL 95
Cdd:cd08852   107 RAKYVEKKFI 116

ARF1 GTPase-activating protein 1-like; ArfGAP (ADP Ribosylation Factor GTPase Activating Protein) domain is a part of ArfGap1-like proteins that play a crucial role in controlling of membrane trafficking, particularly in the formation of COPI (coat protein complex I)-coated vesicles on Golgi membranes. The ArfGAP1 protein subfamily consists of three members: ArfGAP1 (Gcs1p in yeast), ArfGAP2 and ArfGAP3 (both are homologs of yeast Glo3p). ArfGAP2/3 are closely related, but with little similarity to ArfGAP1, except the catalytic ArfGAP domain. They promote hydrolysis of GTP bound to the small G protein ADP-ribosylation factor 1 (Arf1), which leads to the dissociation of coat proteins from Golgi-derived membranes and vesicles. Dissociation of the coat proteins is required for the fusion of these vesicles with target compartments. Thus, the GAP catalytic activity plays a key role in the formation of COPI vesicles from Golgi membrane. In contrast to ArfGAP1, which displays membrane curvature-dependent ArfGAP activity, ArfGAP2 and ArfGAP3 activities are dependent on coatomer (the core COPI complex) which required for efficient recruitment of ArfGAP2 and ArfGAP3 to the Golgi membrane. Accordingly, ArfGAP2/3 has been implicated in coatomer-mediated protein transport between the Golgi complex and the endoplasmic reticulum. Unlike ArfGAP1, which is controlled by membrane curvature through its amphipathic lipid packing sensor (ALPS) motifs, ArfGAP2/3 do not possess ALPS motif.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMiEIGGNASAN 58
Cdd:cd08959    29 SVTYGIFICLDCSGVHRGLGVHISFVRSTTMDKWTEEQLRKM-KVGGNANAR 79

ArfGAP domain of ACAP3 (ArfGAP with Coiled-coil, ANK repeat and PH domains 3); ACAP3 belongs to the ACAP subfamily of GAPs (GTPase-activating proteins) for the small GTPase Arf (ADP-ribosylation factor). ACAP subfamily of ArfGAPs are composed of Coiled coli (BAR, Bin-Amphiphysin-Rvs), PH, ArfGAP and ANK repeats domains. It has been shown that ACAP3 positively regulates neurite outgrowth through its GAP activity specific to Arf6 in mouse hippocampal neurons. ACAP1 (centaurin beta1) and ACAP2 centaurin beta2) also have a GAP (GTPase-activating protein) activity preferentially toward Arf6, which regulates endocytic recycling. Both ACAP1/2 are activated by are activated by the phosphoinositides, PI(4,5)P2 and PI(3,5)P2. ACAP1 binds specifically with recycling cargo proteins such as transferrin receptor (TfR) and cellubrevin. Thus, ACAP1 promotes cargo sorting to enhance TfR recycling from the recycling endosome. In addition, phosphorylation of ACAP by Akt, a serine/threonine protein kinase, regulates the recycling of integrin beta1 to control cell migration. In contrast, ACAP2 does not exhibit a similar interaction with the recycling cargo proteins. It has been shown that ACAP2 functions both as an effector of Ras-related protein Rab35 and as an Arf6-GTPase-activating protein (GAP) during neurite outgrowth of PC12 cells. Moreover, ACAP2, together with Rab35, regulates phagocytosis in mammalian macrophages.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLPDTCS-KPGPDVNHDQRMRFI 85
Cdd:cd08850    28 SINLGILLCIECSGIHRSLGVHCSKVRSLTLDSWEPELLKLMCEL-GNSTVNQIYEAQCEELGLkKPTASSSRQDKEAWI 106

                          90
                  ....*....|
gi 1063721150  86 RAKYELQEFL 95
Cdd:cd08850   107 KAKYVEKKFL 116

Arf1 GTPase-activating protein 1; ArfGAP (ADP Ribosylation Factor GTPase Activating Protein) domain is a part of ArfGap1-like proteins that play a crucial role in controlling of membrane trafficking, particularly in the formation of COPI (coat protein complex I)-coated vesicles on Golgi membranes. The ArfGAP1 protein subfamily consists of three members: ArfGAP1 (Gcs1p in yeast), ArfGAP2 and ArfGAP3 (both are homologs of yeast Glo3p). ArfGAP2/3 are closely related, but with little similarity to ArfGAP1, except the catalytic ArfGAP domain. They promote hydrolysis of GTP bound to the small G protein ADP-ribosylation factor 1 (Arf1), which leads to the dissociation of coat proteins from Golgi-derived membranes and vesicles. Dissociation of the coat proteins is required for the fusion of these vesicles with target compartments. Thus, the GAP catalytic activity plays a key role in the formation of COPI vesicles from Golgi membrane. In contrast to ArfGAP1, which displays membrane curvature-dependent ArfGAP activity, ArfGAP2 and ArfGAP3 activities are dependent on coatomer (the core COPI complex) which required for efficient recruitment of ArfGAP2 and ArfGAP3 to the Golgi membrane. Accordingly, ArfGAP2/3 has been implicated in coatomer-mediated protein transport between the Golgi complex and the endoplasmic reticulum. Unlike ArfGAP1, which is controlled by membrane curvature through its amphipathic lipid packing sensor (ALPS) motifs, ArfGAP2/3 do not possess ALPS motif.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMiEIGGNASANS 59
Cdd:cd08830    29 SVSYGIFICLECSGVHRGLGVHISFVRSITMDSWSEKQLKKM-ELGGNAKLRE 80

Arf1 GTPase-activating protein 2/3-like; ArfGAP (ADP Ribosylation Factor GTPase Activating Protein) domain is a part of ArfGap1-like proteins that play a crucial role in controlling of membrane trafficking, particularly in the formation of COPI (coat protein complex I)-coated vesicles on Golgi membranes. The ArfGAP1 protein subfamily consists of three members: ArfGAP1 (Gcs1p in yeast), ArfGAP2 and ArfGAP3 (both are homologs of yeast Glo3p). ArfGAP2/3 are closely related, but with little similarity to ArfGAP1, except the catalytic ArfGAP domain. They promote hydrolysis of GTP bound to the small G protein ADP-ribosylation factor 1 (Arf1), which leads to the dissociation of coat proteins from Golgi-derived membranes and vesicles. Dissociation of the coat proteins is required for the fusion of these vesicles with target compartments. Thus, the GAP catalytic activity plays a key role in the formation of COPI vesicles from Golgi membrane. In contrast to ArfGAP1, which displays membrane curvature-dependent ArfGAP activity, ArfGAP2 and ArfGAP3 activities are dependent on coatomer (the core COPI complex) which required for efficient recruitment of ArfGAP2 and ArfGAP3 to the Golgi membrane. Accordingly, ArfGAP2/3 has been implicated in coatomer-mediated protein transport between the Golgi complex and the endoplasmic reticulum. Unlike ArfGAP1, which is controlled by membrane curvature through its amphipathic lipid packing sensor (ALPS) motifs, ArfGAP2/3 do not possess ALPS motif.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMiEIGGNASANS 59
Cdd:cd08831    30 SVTFGVFLCLDCSGVHRSLGVHISFVRSTNLDSWTPEQLRRM-KVGGNAKARE 81

ArfGAP domain of ACAP2 (ArfGAP with Coiled-coil, ANK repeat and PH domains 2); ACAP2 belongs to the ACAP subfamily of GAPs (GTPase-activating proteins) for the small GTPase Arf (ADP-ribosylation factor). ACAP subfamily of ArfGAPs are composed of Coiled coli (BAR, Bin-Amphiphysin-Rvs), PH, ArfGAP and ANK repeats domains. ACAP1 (centaurin beta1) and ACAP2 centaurin beta2) have a GAP (GTPase-activating protein) activity preferentially toward Arf6, which regulates endocytic recycling. Both ACAP1/2 are activated by are activated by the phosphoinositides, PI(4,5)P2 and PI(3,5)P2. ACAP1 binds specifically with recycling cargo proteins such as transferrin receptor (TfR) and cellubrevin. Thus, ACAP1 promotes cargo sorting to enhance TfR recycling from the recycling endosome. In addition, phosphorylation of ACAP by Akt, a serine/threonine protein kinase, regulates the recycling of integrin beta1 to control cell migration. In contrast, ACAP2 does not exhibit a similar interaction with the recycling cargo proteins. It has been shown that ACAP2 functions both as an effector of Ras-related protein Rab35 and as an Arf6-GTPase-activating protein (GAP) during neurite outgrowth of PC12 cells. Moreover, ACAP2, together with Rab35, regulates phagocytosis in mammalian macrophages. ACAP3 also positively regulates neurite outgrowth through its GAP activity specific to Arf6 in mouse hippocampal neurons.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLPDT-CSKPGPDVNHDQRMRFI 85
Cdd:cd08851    28 SINLGITLCIECSGIHRSLGVHFSKVRSLTLDTWEPELLKLMCEL-GNDVINRIYEARVEKMgAKKPQPGGQRQEKEAYI 106

                          90
                  ....*....|
gi 1063721150  86 RAKYELQEFL 95
Cdd:cd08851   107 RAKYVERKFV 116

C2 domain first repeat; fungal group; C2 domains were first identified in Protein Kinase C (PKC). C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 145 GLLKVTIKKGTNLAIRD--MMSSDPYVVLNLGK-QKL--QTTVMNSNLNPVWNQE-LMLSVPESYGP---VKLQVYDYDT 215
Cdd:cd04041     1 GVLVVTIHRATDLPKADfgTGSSDPYVTASFAKfGKPlySTRIIRKDLNPVWEETwFVLVTPDEVKAgerLSCRLWDSDR 80

                          90
                  ....*....|....*...
gi 1063721150 216 FSADDIMGEADIDIQPLI 233
Cdd:cd04041    81 FTADDRLGRVEIDLKELI 98

ADAP2 GTPase activating protein for Arf, with dual PH domains; The ADAP subfamily, ArfGAPs with dual pleckstrin homology (PH) domains, includes two members: ADAP1 and ADAP2. Both ADAP1 (also known as centaurin-alpha1, p42(IP4), or PIP3BP) and ADAP2 (centaurin-alpha2) display a GTPase-activating protein (GAP) activity toward Arf6 (ADP-ribosylation factor 6), which is involved in protein trafficking that regulates endocytic recycling, cytoskeleton remodeling, and neuronal differentiation. ADAP2 has high sequence similarity to the ADAP1 and they both contain a ArfGAP domain at the N-terminus, followed by two PH domains. However, ADAP1, unlike ADAP2, contains a putative N-terminal nuclear localization signal. The PH domains of ADAP1bind to the two second messenger molecules phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) and inositol 1,3,4,5-tetrakisphosphate (I(1,3,4,5)P4) with identical high affinity, whereas those of ADAP2 specifically binds phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) and PI(3,4,5)P3, which are produced by activated phosphatidylinositol 3-kinase. ADAP1 is predominantly expressed in the brain neurons, while ADAP2 is broadly expressed, including the adipocytes, heart, and skeletal muscle but not in the brain. The limited distribution and high expression of ADAP1 in the brain indicates that ADAP1 is important for neuronal functions. ADAP1 has been shown to highly expressed in the neurons and plagues of Alzheimer's disease patients. In other hand, ADAP2 gene deletion has been shown to cause circulatory deficiencies and heart shape defects in zebrafish, indicating that ADAP2 has a vital role in heart development. Taken together, the hemizygous deletion of ADAP2 gene may be contributing to the cardiovascular malformation in patients with neurofibromatosis type 1 (NF1) microdeletions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLgTHISKVLSVTLDEWSDEEVDSMIEiGGNASANSIYEAFLPDTCSKPGP---DVNHDQrmr 83
Cdd:cd08844    32 SYTLGIFICLNCSGVHRNL-PDISRVKSIRLDFWEDELVEFMKE-NGNLKAKAKFEAFVPPFYYRPQAndcDVLKEQ--- 106

                  ....*.
gi 1063721150  84 FIRAKY 89
Cdd:cd08844   107 WIRAKY 112

ArfGAP domain of ASAP3 (ArfGAP with ANK repeat and PH domain-containing protein 3); The ArfGAPs are a family of multidomain proteins with a common catalytic domain that promotes the hydrolysis of GTP bound to Arf, thereby inactivating Arf signaling. ASAP-subfamily GAPs include three members: ASAP1, ASAP2, ASAP3. The ASAP subfamily comprises Arf GAP, SH3, ANK repeat and PH domains. From the N-terminus, each member has a BAR, PH, Arf GAP, ANK repeat, and proline rich domains. Unlike ASAP1 and ASAP2, ASAP3 do not have an SH3 domain at the C-terminus. ASAP1 and ASAP2 show strong GTPase-activating protein (GAP) activity toward Arf1 and Arf5 and weak activity toward Arf6. ASAP1 is a target of Src and FAK signaling that regulates focal adhesions, circular dorsal ruffles (CDR), invadopodia, and podosomes. ASAP1 GAP activity is synergistically stimulated by phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidic acid. ASAP2 is believed to function as an ArfGAP that controls ARF-mediated vesicle budding when recruited to Golgi membranes. It also functions as a substrate and downstream target for protein tyrosine kinases Pyk2 and Src, a pathway that may be involved in the regulation of vesicular transport. ASAP3 is a focal adhesion-associated ArfGAP that functions in cell migration and invasion. Similar to ASAP1, the GAP activity of ASAP3 is strongly enhanced by PIP2 via PH domain. Like ASAP1, ASAP3 associates with focal adhesions and circular dorsal ruffles. However, unlike ASAP1, ASAP3 does not localize to invadopodia or podosomes. ASAP 1 and 3 have been implicated in oncogenesis, as ASAP1 is highly expressed in metastatic breast cancer and ASAP3 in hepatocellular carcinoma.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDEWSDEEVDSMIEIgGNASANSIYEAFLPDT-CSKPGPDVNHDQRMRFI 85
Cdd:cd17900    30 STNLGILTCIECSGIHRELGVRYSRIQSLTLDLLSTSELLLAVSM-GNTRFNEVMEATLPAHgGPKPSAESDMGTRKDYI 108

                          90
                  ....*....|...
gi 1063721150  86 RAKYELQEFLKPS 98
Cdd:cd17900   109 MAKYVEHRFVRKR 121

ArfGAP domain of the AGFG subfamily (ArfGAP domain and FG repeat-containing proteins); The ArfGAP domain and FG repeat-containing proteins (AFGF) subfamily of Arf GTPase-activating proteins consists of the two structurally-related members: AGFG1 and AGFG2. AGFG1 (alias: HIV-1 Rev binding protein, HRB; Rev interacting protein, RIP; Rev/Rex activating domain-binding protein, RAB) and AGFG2 are involved in the maintenance and spread of immunodeficiency virus type 1 (HIV-1) infection. The ArfGAP domain of AGFG is related to nucleoporins, which is a class of proteins that mediate nucleocytoplasmic transport. AGFG plays a role in the Rev export pathway, which mediates the nucleocytoplasmic transfer of proteins and RNAs, possibly together by the nuclear export receptor CRM1. In humans, the presence of the FG repeat motifs (11 in AGFG1 and 7 in AGFG2) are thought to be required for these proteins to act as HIV-1 Rev cofactors. Hence, AGFG promotes movement of Rev-responsive element-containing RNAs from the nuclear periphery to the cytoplasm, which is an essential step for HIV-1 replication.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   9 NIGVFICLKCCGVHRSLGtHisKVLSVTLDEWSDEEVDsMIEIGGNASANSIYEAFLPDTCSKPgPDVNHDQRMR-FIRA 87
Cdd:cd08838    30 TFGTFVCTTCSGIHREFN-H--RVKSISMSTFTPEEVE-FLQAGGNEVARKIWLAKWDPRTDPE-PDSGDDQKIReFIRL 104

                  ...
gi 1063721150  88 KYE 90
Cdd:cd08838   105 KYV 107

ArfGap with Rho-Gap domain, ANK repeat and PH domain-containing protein 3; The ARAP subfamily includes three members, ARAP1-3, and belongs to the ADP-ribosylation factor GTPase-activating proteins (Arf GAPs) family of proteins that promotes the hydrolysis of GTP bound to Arf, thereby inactivating Arf signaling. The function of Arfs is dependent on GAPs and guanine nucleotide exchange factors (GEFs), which allow Arfs to cycle between the GDP-bound and GTP-bound forms. In addition to the Arf GAP domain, ARAPs contain the SAM (sterile-alpha motif) domain, 5 pleckstrin homology (PH) domains, the Rho-GAP domain, the Ras-association domain, and ANK repeats. ARAPs show phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3)-dependent GAP activity toward Arf6. ARAPs play important roles in endocytic trafficking, cytoskeleton reorganization in response to growth factors stimulation, and focal adhesion dynamics. ARAP3 possesses a unique dual-specificity GAP activity for Arf6 and RhoA regulated by PI(3,4,5)P3 and a small GTPase Rap1-GTP. The RhoGAP activity of ARAP3 is enhanced by direct binding of Rap1-GTP to the Ras-association (RA) domain. ARAP3 is involved in regulation of cell shape and adhesion.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLGTHISKVLSVTLDE--WSDEEVDSMIEIgGNASANSIYEAFLPdtcskPG----PDVNHDQ 80
Cdd:cd17902    28 SINLCVVICKQCAGQHRSLGSGISKVQSLKLDTsvWSNEIVQLFIVL-GNDRANRFWAARLP-----ASealhPDATPEQ 101

                          90
                  ....*....|....
gi 1063721150  81 RMRFIRAKYELQEF 94
Cdd:cd17902   102 RREFISRKYREGRF 115

ADAP1 GTPase activating protein for Arf, with dual PH domains; The ADAP subfamily, ArfGAPs with dual pleckstrin homology (PH) domains, includes two members: ADAP1 and ADAP2. Both ADAP1 (also known as centaurin-alpha1, p42(IP4), or PIP3BP) and ADAP2 (centaurin-alpha2) display a GTPase-activating protein (GAP) activity toward Arf6 (ADP-ribosylation factor 6), which is involved in protein trafficking that regulates endocytic recycling, cytoskeleton remodeling, and neuronal differentiation. ADAP2 has high sequence similarity to the ADAP1 and they both contain a ArfGAP domain at the N-terminus, followed by two PH domains. However, ADAP1, unlike ADAP2, contains a putative N-terminal nuclear localization signal. The PH domains of ADAP1bind to the two second messenger molecules phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) and inositol 1,3,4,5-tetrakisphosphate (I(1,3,4,5)P4) with identical high affinity, whereas those of ADAP2 specifically binds phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) and PI(3,4,5)P3, which are produced by activated phosphatidylinositol 3-kinase. ADAP1 is predominantly expressed in the brain neurons, while ADAP2 is broadly expressed, including the adipocytes, heart, and skeletal muscle but not in the brain. The limited distribution and high expression of ADAP1 in the brain indicates that ADAP1 is important for neuronal functions. ADAP1 has been shown to highly expressed in the neurons and plagues of Alzheimer's disease patients. In other hand, ADAP2 gene deletion has been shown to cause circulatory deficiencies and heart shape defects in zebrafish, indicating that ADAP2 has a vital role in heart development. Taken together, the hemizygous deletion of ADAP2 gene may be contributing to the cardiovascular malformation in patients with neurofibromatosis type 1 (NF1) microdeletions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150   7 SANIGVFICLKCCGVHRSLgTHISKVLSVTLDEWSDEEVDSMIEIGGNAsANSIYEAFLPDTCSKPGPDVNHDQRMRFIR 86
Cdd:cd08843    32 SYTLGVFICLSCSGIHRNI-PQVSKVKSVRLDAWEEAQVEFMASHGNDA-ARARFESKVPSFYYRPTPSDCQLLREQWIR 109

                  ...
gi 1063721150  87 AKY 89
Cdd:cd08843   110 AKY 112

C2 domain fourth repeat present in Tricalbin-like proteins; 5 to 6 copies of the C2 domain are present in Tricalbin, a yeast homolog of Synaptotagmin, which is involved in membrane trafficking and sorting. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the fifth C2 repeat, C2E, and has a type-II topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 147 LKVTIKKGTNLairdmMS------SDPYVVLNL-GKQKLQTTVMNSNLNPVWNQELMLSVPESYGP-VKLQVYDYDTFSA 218
Cdd:cd04040     1 LTVDVISAENL-----PSadrngkSDPFVKFYLnGEKVFKTKTIKKTLNPVWNESFEVPVPSRVRAvLKVEVYDWDRGGK 75

                          90
                  ....*....|....
gi 1063721150 219 DDIMGEADIDIQPL 232
Cdd:cd04040    76 DDLLGSAYIDLSDL 89

C2A domain first repeat present in Synaptotagmin 7; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Synaptotagmin 7, a member of class 2 synaptotagmins, is located in presynaptic plasma membranes in neurons, dense-core vesicles in endocrine cells, and lysosomes in fibroblasts. It has been shown to play a role in regulation of Ca2+-dependent lysosomal exocytosis in fibroblasts and may also function as a vesicular Ca2+-sensor. It is distinguished from the other synaptotagmins by having over 12 splice forms. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the first C2 repeat, C2A, and has a type-I topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 147 LKVTIKKGTNLAIRDMM-SSDPYVVLNL---GKQKLQTTVMNSNLNPVWNqELMLSVPESYGPVK-----LQVYDYDTFS 217
Cdd:cd08386    18 LTLKILKAVELPAKDFSgTSDPFVKIYLlpdKKHKLETKVKRKNLNPHWN-ETFLFEGFPYEKLQqrvlyLQVLDYDRFS 96

                          90
                  ....*....|..
gi 1063721150 218 ADDIMGEADIDI 229
Cdd:cd08386    97 RNDPIGEVSLPL 108

C2 domain fifth repeat in Ferlin; Ferlins are involved in vesicle fusion events. Ferlins and other proteins, such as Synaptotagmins, are implicated in facilitating the fusion process when cell membranes fuse together. There are six known human Ferlins: Dysferlin (Fer1L1), Otoferlin (Fer1L2), Myoferlin (Fer1L3), Fer1L4, Fer1L5, and Fer1L6. Defects in these genes can lead to a wide range of diseases including muscular dystrophy (dysferlin), deafness (otoferlin), and infertility (fer-1, fertilization factor-1). Structurally they have 6 tandem C2 domains, designated as (C2A-C2F) and a single C-terminal transmembrane domain, though there is a new study that disputes this and claims that there are actually 7 tandem C2 domains with another C2 domain inserted between C2D and C2E. In a subset of them (Dysferlin, Myoferlin, and Fer1) there is an additional conserved domain called DysF. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the fifth C2 repeat, C2E, and has a type-II topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 146 LLKVTIKKGTNLAIRDMMS-SDPYVVLNLGKQKL---QTTVMNsNLNPVWNQ--ELMLSVPESyGPVKLQVYDYDTFSAD 219
Cdd:cd04037     1 LVRVYVVRARNLQPKDPNGkSDPYLKIKLGKKKIndrDNYIPN-TLNPVFGKmfELEATLPGN-SILKISVMDYDLLGSD 78

                          90
                  ....*....|
gi 1063721150 220 DIMGEADIDI 229
Cdd:cd04037    79 DLIGETVIDL 88

C2 domain present in the Human neural precursor cell-expressed, developmentally down-regulated 4 (NEDD4) and NEDD4-like (NEDD4L/NEDD42); Nedd4 and Nedd4-2 are two of the nine members of the Human Nedd4 family. All vertebrates appear to have both Nedd4 and Nedd4-2 genes. They are thought to participate in the regulation of epithelial Na+ channel (ENaC) activity. They also have identical specificity for ubiquitin conjugating enzymes (E2). Nedd4 and Nedd4-2 are composed of a C2 domain, 2-4 WW domains, and a ubiquitin ligase Hect domain. Their WW domains can bind PPxY (PY) or LPSY motifs, and in vitro studies suggest that WW3 and WW4 of both proteins bind PY motifs in the key substrates, with WW3 generally exhibiting higher affinity. Most Nedd4 family members, especially Nedd4-2, also have multiple splice variants, which might play different roles in regulating their substrates. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1063721150 146 LLKVTIKKGTNLAIRDMM-SSDPYVVLNLGKQK-------LQTTVMNSNLNPVWNQELMLSVPESYGPVKLQVYDYDTFS 217
Cdd:cd04033     1 ILRVKVLAGIDLAKKDIFgASDPYVKISLYDPDgngeidsVQTKTIKKTLNPKWNEEFFFRVNPREHRLLFEVFDENRLT 80