Kazal type serine protease inhibitors and follistatin-like domains. Kazal inhibitors inhibit serine proteases, such as, trypsin, chyomotrypsin, avian ovomucoids, and elastases. The inhibitory domain has one reactive site peptide bond, which serves the cognate enzyme as substrate. The reactive site peptide bond is a combining loop which has an identical conformation in all Kazal inhibitors and in all enzyme/inhibitor complexes. These Kazal domains (small hydrophobic core of alpha/beta structure with 3 to 4 disulfide bonds) often occur in tandem arrays. Similar domains are also present in follistatin (FS) and follistatin-like family members, which play an important role in tissue specific regulation. The FS domain consists of an N-terminal beta hairpin (FOLN/EGF-like domain) and a Kazal-like domain and has five disulfide bonds. Although the Kazal-like FS substructure is similar to Kazal proteinase inhibitors, no FS domain has yet been shown to be a proteinase inhibitor. Follistatin-like family members include SPARC, also known as, BM-40 or osteonectin, the Gallus gallus Flik protein, as well as, agrin which has a long array of FS domains. The kazal-type inhibitor domain has also been detected in an extracellular loop region of solute carrier 21 (SLC21) family members (organic anion transporters) , which may regulate the specificity of anion uptake. The distant homolog, Ascidian trypsin inhibitor, is included in this CD.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|.
gi 49523315  93 CKQHYKPVCGSDGEFYENHCEVHRAACLKKQKITIVHNEDC 133
Cdd:cd00104   1 CPKEYDPVCGSDGKTYSNECHLGCAACRSGRSITVAHNGPC 41

DNA-binding beta-propeller fold protein YncE [General function prediction only];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 512 KFIYVAQPTLDRILIVDVQSQKVVQAVSTDPVPVKLHYDKSHDQVWVLSWGsmektSPTLQVITLASGNVphhtIHTQPV 591
Cdd:COG3391  80 RRLYVANSGSGRVSVIDLATGKVVATIPVGGGPRGLAVDPDGGRLYVADSG-----NGRVSVIDTATGKV----VATIPV 150

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 49523315 592 GKQ-----FDRVDDffiptpTLIITHMRFGFILHkdesALHKIDLETMSYIKTINLKDSrciPLSLAYTHLGGYYFISC 665
Cdd:COG3391 151 GAGphgiaVDPDGK------RLYVANSGSNTVSV----IVSVIDTATGKVVATIPVGGG---PVGVAVSPDGRRLYVAN 216

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 49523315   340 PPVIRVYPESQAREPGVTASLRCHAEGIPDPQLGWLKNGIDITPKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARN 417
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Kazal type serine protease inhibitors and follistatin-like domains. Kazal inhibitors inhibit serine proteases, such as, trypsin, chyomotrypsin, avian ovomucoids, and elastases. The inhibitory domain has one reactive site peptide bond, which serves the cognate enzyme as substrate. The reactive site peptide bond is a combining loop which has an identical conformation in all Kazal inhibitors and in all enzyme/inhibitor complexes. These Kazal domains (small hydrophobic core of alpha/beta structure with 3 to 4 disulfide bonds) often occur in tandem arrays. Similar domains are also present in follistatin (FS) and follistatin-like family members, which play an important role in tissue specific regulation. The FS domain consists of an N-terminal beta hairpin (FOLN/EGF-like domain) and a Kazal-like domain and has five disulfide bonds. Although the Kazal-like FS substructure is similar to Kazal proteinase inhibitors, no FS domain has yet been shown to be a proteinase inhibitor. Follistatin-like family members include SPARC, also known as, BM-40 or osteonectin, the Gallus gallus Flik protein, as well as, agrin which has a long array of FS domains. The kazal-type inhibitor domain has also been detected in an extracellular loop region of solute carrier 21 (SLC21) family members (organic anion transporters) , which may regulate the specificity of anion uptake. The distant homolog, Ascidian trypsin inhibitor, is included in this CD.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|.
gi 49523315  93 CKQHYKPVCGSDGEFYENHCEVHRAACLKKQKITIVHNEDC 133
Cdd:cd00104   1 CPKEYDPVCGSDGKTYSNECHLGCAACRSGRSITVAHNGPC 41

Kazal type serine protease inhibitors; Kazal type serine protease inhibitors and follistatin-like domains.

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|....*
gi 49523315     89 CMDLCKQHYKPVCGSDGEFYENHCEVHRAACLKKQKITIVHNEDC 133
Cdd:smart00280   2 CPEACPREYDPVCGSDGVTYSNECHLCKAACESGKSIEVKHDGPC 46

DNA-binding beta-propeller fold protein YncE [General function prediction only];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 512 KFIYVAQPTLDRILIVDVQSQKVVQAVSTDPVPVKLHYDKSHDQVWVLSWGsmektSPTLQVITLASGNVphhtIHTQPV 591
Cdd:COG3391  80 RRLYVANSGSGRVSVIDLATGKVVATIPVGGGPRGLAVDPDGGRLYVADSG-----NGRVSVIDTATGKV----VATIPV 150

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 49523315 592 GKQ-----FDRVDDffiptpTLIITHMRFGFILHkdesALHKIDLETMSYIKTINLKDSrciPLSLAYTHLGGYYFISC 665
Cdd:COG3391 151 GAGphgiaVDPDGK------RLYVANSGSNTVSV----IVSVIDTATGKVVATIPVGGG---PVGVAVSPDGRRLYVAN 216

Kazal-type serine protease inhibitor domain; Usually indicative of serine protease inhibitors. However, kazal-like domains are also seen in the extracellular part of agrins, which are not known to be protease inhibitors. Kazal domains often occur in tandem arrays. Small alpha+beta fold containing three disulphides.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 49523315    86 ECACMDLckqHYKPVCGSDGEFYENHCEVHRAACLKKQKI---TIVHNEDC 133
Cdd:pfam07648   3 NCQCPKT---EYEPVCGSDGVTYPSPCALCAAGCKLGKEVkeeKVKYDGSC 50

EF-hand motif found in eukaryotic phosphoinositide-specific phospholipase C (PI-PLC, EC 3.1.4.11) isozymes; PI-PLC isozymes are signaling enzymes that hydrolyze the membrane phospholipids phosphatidylinositol-4,5-bisphosphate (PIP2) to generate two important second messengers in eukaryotic signal transduction cascades, Inositol 1,4,5-trisphosphate (InsP3) and diacylglycerol (DAG). InsP3 triggers inflow of calcium from intracellular stores, while DAG, together with calcium, activates protein kinase C, which goes on to phosphorylate other molecules, leading to altered cellular activity. Calcium is required for the catalysis. This family corresponds to the four EF-hand motifs containing PI-PLC isozymes, including PI-PLC-beta (1-4), -gamma (1-2), -delta (1,3,4), -epsilon (1), -zeta (1), eta (1-2). Lower eukaryotes such as yeast and slime molds contain only delta-type isozymes. In contrast, other types of isoforms present in higher eukaryotes. This family also includes 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase 1 (PLC1) from fungi. Some homologs from plants contain only two atypical EF-hand motifs and they are not included. All PI-PLC isozymes except sperm-specific PI-PLC-zeta share a core set of domains, including an N-terminal pleckstrin homology (PH) domain, four atypical EF-hand motifs, a PLC catalytic core, and a single C2 domain. PI-PLC-zeta lacks the PH domain. The PLC catalytic core domain is a TIM barrel with two highly conserved regions (X and Y) split by a highly degenerate linker sequence. Most of EF-hand motifs found in PI-PLCs consist of a helix-loop-helix structure, but lack residues critical to metal binding. Moreover, the EF-hand region of most of PI-PLCs may have an important regulatory function, but it has yet to be identified. However, PI-PLC-zeta is a key exception. It is responsible for Ca2+ oscillations in fertilized oocytes and exhibits a high sensitivity to Ca2+ mediated through its EF-hand domain. In addition, PI-PLC-eta2 shows a canonical EF-loop directing Ca2+-sensitivity and thus can amplify transient Ca2+ signals. Also it appears that PI-PLC-delta1 can regulate the binding of PH domain to PIP2 in a Ca2+-dependent manner through its functionally important EF-hand domains. PI-PLCs can be activated by a variety of extracellular ligands, such as growth factors, hormones, cytokines and lipids. Their activation has been implicated in tumorigenesis and/or metastasis linked to migration, proliferation, growth, inflammation, angiogenesis and actin cytoskeleton reorganization. PI-PLC-beta isozymes are activated by G-protein coupled receptor (GPCR) through different mechanisms. However, PI-PLC-gamma isozymes are activated by receptor tyrosine kinase (RTK), such as Rho and Ras GTPases. In contrast, PI-PLC-epsilon are activated by both GPCR and RTK. PI-PLC-delta1 and PLC-eta 1 are activated by GPCR-mediated calcium mobilization. The activation mechanism for PI-PLC-zeta remains unclear.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 49523315 180 VDQMFKYFDADSNGLVDINELTQVIKQeeLNKDLSDCTLYDLLKYDDFNADKHLALEEFYRAF 242
Cdd:cd15898   2 LRRQWIKADKDGDGKLSLKEIKKLLKR--LNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELY 62

EF hand; The EF-hands can be divided into two classes: signalling proteins and buffering/transport proteins. The first group is the largest and includes the most well-known members of the family such as calmodulin, troponin C and S100B. These proteins typically undergo a calcium-dependent conformational change which opens a target binding site. The latter group is represented by calbindin D9k and do not undergo calcium dependent conformational changes.

                          10        20
                  ....*....|....*....|....*.
gi 49523315   180 VDQMFKYFDADSNGLVDINELTQVIK 205
Cdd:pfam00036   2 LKEIFRLFDKDGDGKIDFEEFKELLK 27

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 49523315   340 PPVIRVYPESQAREPGVTASLRCHAEGIPDPQLGWLKNGIDITPKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARN 417
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315    347 PESQAREPGVTASLRCHAEGIPDPQLGWLKNGID-ITPKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARNEAGVDEDI 425
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKlLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

                   ....*
gi 49523315    426 SSLFV 430
Cdd:smart00410  81 TTLTV 85

Fifth Ig-like domain of Roundabout (Robo) homolog 1/2, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fifth Ig-like domain of Roundabout (Robo) homolog 1/2 and similar domains. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, -2, and -3), and three mammalian Slit homologs (Slit-1,-2, -3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, -2, and -3 are expressed by commissural neurons in the vertebrate spinal cord and Slits 1, -2, -3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of slit responsiveness, antagonizes slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. The fifth Ig-like domain of Robo 1 and 2 is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 49523315 342 VIRVYPESQAREPGVTASLRCHAEGIPDPQLGWLKNGIDITPKlSKQLTLQANGSeVHISNVRYEDTGAYTCIARNEAG 420
Cdd:cd20952   1 IILQGPQNQTVAVGGTVVLNCQATGEPVPTISWLKDGVPLLGK-DERITTLENGS-LQIKGAEKSDTGEYTCVALNLSG 77

agrin-responsive first immunoglobulin-like domains (Ig1) of the MuSK ectodomain; a member of the I-set of IgSF domains; The members here are composed of the first immunoglobulin-like domains (Ig1) of the Muscle-specific kinase (MuSK). MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the MuSK lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 341 PVIRVYPES---QAREpGVTASLRCHAEGIPDPQLGWLKNGIDITpKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARN 417
Cdd:cd20970   1 PVISTPQPSftvTARE-GENATFMCRAEGSPEPEISWTRNGNLII-EFNTRYIVRENGTTLTIRNIRRSDMGIYLCIASN 78

                ...
gi 49523315 418 EAG 420
Cdd:cd20970  79 GVP 81

Immunoglobulin (Ig)-like domain of myotilin, palladin, and myopalladin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in myotilin, palladin, and myopalladin. Myotilin, palladin, and myopalladin function as scaffolds that regulate actin organization. Myotilin and myopalladin are most abundant in skeletal and cardiac muscle; palladin is ubiquitously expressed in the organs of developing vertebrates and plays a key role in cellular morphogenesis. The three family members each interact with specific molecular partners with all three binding to alpha-actinin; In addition, palladin also binds to vasodilator-stimulated phosphoprotein (VASP) and ezrin, myotilin binds to filamin and actin, and myopalladin also binds to nebulin and cardiac ankyrin repeat protein (CARP). This group belongs to the I-set of IgSF domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 49523315 355 GVTASLRCHAEGIPDPQLGWLKNGIDITPKLSKQLTLQANGS-EVHISNVRYEDTGAYTCIARNEAGVDEDISSLFV 430
Cdd:cd05744  15 GRLCRFDCKVSGLPTPDLFWQLNGKPVRPDSAHKMLVRENGRhSLIIEPVTKRDAGIYTCIARNRAGENSFNAELVV 91

Immunoglobulin (Ig)-like ectodomain of the LRIG1 (Leucine-rich Repeats And Immunoglobulin-like Domains Protein 1) and similar proteins; member of the I-set of IgSF domains; The members here are composed of subgroup of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. The ectodomain of LRIG1 has two distinct regions: the proposed 15 LRRs and three Ig-like domains closer to the membrane. LRIG1 has been reported to interact with many receptor tyrosine kinases, GDNF/c-Ret, E-cadherin, JAK/STAT, c-Met, and the EGFR family signaling systems. Immunoglobulin Superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The structure of the LRIG1 extracellular Ig domain lacks a C" strand and thus is better described as a member of the I-set of IgSF domains.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 49523315 355 GVTASLRCHAEGIPDPQLGWLKNG-IDITPKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARNEAG 420
Cdd:cd05763  14 GSTARLECAATGHPTPQIAWQKDGgTDFPAARERRMHVMPEDDVFFIVDVKIEDTGVYSCTAQNSAG 80

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 49523315   256 SITAATVGQSAVLSCAIVGTLRPPIIWKRNNIVLNNLDLEDINDFGDDGSLYITKVTTVHMGNYTCYA 323
Cdd:pfam13927   9 SSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVA 76

Immunoglobulin domain I1 of the titin I-band and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin domain I1 of the titin I-band and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. The two sheets are linked together by a conserved disulfide bond between B strand and F strand. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The Ig I1 domain of the titin I-band is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 341 PVIRVYPESQAREPGVTASLRCHAEGIPDPQLGWLKNGIDITP-KLSKQLTLQANG--SEVHISNVRYEDTGAYTCIARN 417
Cdd:cd20951   1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYKNGVPIDPsSIPGKYKIESEYgvHVLHIRRVTVEDSAVYSAVAKN 80

                        90
                ....*....|....
gi 49523315 418 EAGVDEDISSLFVE 431
Cdd:cd20951  81 IHGEASSSASVVVE 94

Immunoglobulin (Ig)-like domain in neuregulins; The members here are composed of the immunoglobulin (Ig)-like domain in neuregulins (NRGs). NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. There are four members of the neuregulin gene family (NRG-1, NRG-2, NRG-3, and NRG-4). The NRG-1 protein, binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. The other NRGs proteins bind one or the other or both of these ErbBs. NRG-1 has multiple functions: in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors, while in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. Less is known of the functions of the other NRGs. NRG-2 and NRG-3 are expressed predominantly in the nervous system. NRG-2 is expressed by motor neurons and terminal Schwann cells, and is concentrated near synaptic sites and may be a signal that regulates synaptic differentiation. NRG-4 has been shown to direct pancreatic islet cell development towards the delta-cell lineage.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 349 SQAREPGVTASLRCHAEGI-PDPQLGWLKNGIDITPKLSKQLTLQAN--GSEVHISNVRYEDTGAYTCIARNEAGVDEDI 425
Cdd:cd05750   8 SQTVQEGSKLVLKCEATSEnPSPRYRWFKDGKELNRKRPKNIKIRNKkkNSELQINKAKLEDSGEYTCVVENILGKDTVT 87

                ....*
gi 49523315 426 SSLFV 430
Cdd:cd05750  88 GNVTV 92

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 49523315 266 AVLSCAIVGTLRPPIIWKRNNIVLNNLDLEDINDFGDDGSLYITKVTTVHMGNYTCYA 323
Cdd:cd00096   1 VTLTCSASGNPPPTITWYKNGKPLPPSSRDSRRSELGNGTLTISNVTLEDSGTYTCVA 58

Follistatin-like SPARC (secreted protein, acidic, and rich in cysteines) domain; SPARC/BM-40/osteonectin is a multifunctional glycoprotein which modulates cellular interaction with the extracellular matrix by its binding to structural matrix proteins such as collagen and vitronectin. The protein it composed of an N-terminal acidic region, a follistatin (FS) domain and an EF-hand calcium binding domain. The FS domain consists of an N-terminal beta hairpin (FOLN/EGF-like domain) and a small hydrophobic core of alpha/beta structure (Kazal domain) and has five disulfide bonds and a conserved N-glycosylation site. The FSL_SPARC domain is a member of the superfamily of kazal-like proteinase inhibitors and follistatin-like proteins.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 49523315  65 CENKYCGLGRHCVINrETRHAECACMDLCKQHYKP---VCGSDGEFYENHCEVHRAACLKKQK 124
Cdd:cd01328   2 CENHHCGAGKVCEVD-DENTPKCVCIDPCPEEVDDrrkVCTNDNETFDSDCELYRTRCLCKGG 63

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM), and similar domains; The members here are composed of the third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, and spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM and human neurofascin.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 49523315 355 GVTASLRCHAEGIPDPQLGWLKNGIDItpkLSKQLTLQANGSEVHISNVRYEDTGAYTCIARNEAG 420
Cdd:cd05731  10 GGVLLLECIAEGLPTPDIRWIKLGGEL---PKGRTKFENFNKTLKIENVSEADSGEYQCTASNTMG 72

Fourth immunoglobulin (Ig)-like domain of hemolin, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain of hemolin and similar proteins. Hemolin, an insect immunoglobulin superfamily (IgSF) member containing four Ig-like domains, is a lipopolysaccharide-binding immune protein induced during bacterial infection. Hemolin shares significant sequence similarity with the first four Ig-like domains of the transmembrane cell adhesion molecules (CAMs) of the L1 family. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The fourth Ig-like domain of hemolin is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 49523315 347 PESQ-AREPGVTASLRCHAEGIPDPQLGWLKNGIDITPKlSKQLTLQANGseVHISNVRYEDTGAYTCIARNEAG 420
Cdd:cd20978   7 PEKNvVVKGGQDVTLPCQVTGVPQPKITWLHNGKPLQGP-MERATVEDGT--LTIINVQPEDTGYYGCVATNEIG 78

Second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor, and similar domains; member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor. FGF receptors bind FGF signaling polypeptides. FGFs participate in multiple processes such as morphogenesis, development, and angiogenesis. FGFs bind to four FGF receptor tyrosine kinases (FGFR1, FGFR2, FGFR3, FGFR4). Receptor diversity is controlled by alternative splicing producing splice variants with different ligand binding characteristics and different expression patterns. FGFRs have an extracellular region comprised of three Ig-like domains, a single transmembrane helix, and an intracellular tyrosine kinase domain. Ligand binding and specificity reside in the Ig-like domains 2 and 3, and the linker region that connects these two. FGFR activation and signaling depend on FGF-induced dimerization, a process involving cell surface heparin or heparin sulfate proteoglycans. This group also contains fibroblast growth factor (FGF) receptor like-1(FGFRL1). FGFRL1 does not have a protein tyrosine kinase domain at its C-terminus; neither does its cytoplasmic domain appear to interact with a signaling partner. It has been suggested that FGFRL1 may not have any direct signaling function, but instead acts as a decoy receptor trapping FGFs and preventing them from binding other receptors.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 49523315 351 AREPGVTASLRCHAEGIPDPQLGWLKNGIDITPKLSKQLT-LQANGSEVHISNVRYEDTGAYTCIARNEAG 420
Cdd:cd05729  15 ALPAANKVRLECGAGGNPMPNITWLKDGKEFKKEHRIGGTkVEEKGWSLIIERAIPRDKGKYTCIVENEYG 85

DNA-binding beta-propeller fold protein YncE [General function prediction only];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 512 KFIYVAQPTLDRILIVDVQSQKVVQAVSTDPVPVKLHYDKSHDQVWVLSWGsmektSPTLQVITLASGNVphhtIHTQPV 591
Cdd:COG3391  80 RRLYVANSGSGRVSVIDLATGKVVATIPVGGGPRGLAVDPDGGRLYVADSG-----NGRVSVIDTATGKV----VATIPV 150

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 49523315 592 GKQ-----FDRVDDffiptpTLIITHMRFGFILHkdesALHKIDLETMSYIKTINLKDSrciPLSLAYTHLGGYYFISC 665
Cdd:COG3391 151 GAGphgiaVDPDGK------RLYVANSGSNTVSV----IVSVIDTATGKVVATIPVGGG---PVGVAVSPDGRRLYVAN 216

Fourth immunoglobulin (Ig)-like domain of NrCAM (NgCAM-related cell adhesion molecule); The members here are composed of the fourth immunoglobulin (Ig)-like domain of NrCAM (NgCAM-related cell adhesion molecule). NrCAM belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six IG-like domains and five fibronectin type III domains, a transmembrane region, and an intracellular domain. NrCAM is primarily expressed in the nervous system.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 49523315 347 PESQAREPGVTASLRCHAEGIPDPQLGWLKNG--IDITPKLSKQltlQANGSEVHISNVRYEDTGAYTCIARNEAG 420
Cdd:cd05868   6 PTNLVLSPGEDGTLICRANGNPKPSISWLTNGvpIEIAPTDPSR---KVDGDTIIFSKVQERSSAVYQCNASNEYG 78

First immunoglobulin (Ig)-like constant domain in Robo (roundabout) receptors, and similar domains; The members here are composed of the first immunoglobulin (Ig)-like domain in Roundabout (Robo) receptors. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, Robo2, and Robo3), and three mammalian Slit homologs (Slit1, Slit2, Slit3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, Robo2, and Robo3 are expressed by commissural neurons in the vertebrate spinal cord and Slit1, Slit2,and Slit3 are expressed at the ventral midline. Robo3 is a divergent member of the Robo family which instead of being a positive regulator of Slit responsiveness, antagonizes Slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 341 PVIRVYPESQAREPGVTASLRCHAEGIPDPQLGWLKNG----IDITPKLSKQLTLQANG----SEVHISNVRyEDTGAYT 412
Cdd:cd07693   1 PRIVEHPSDLIVSKGDPATLNCKAEGRPTPTIQWLKNGqpleTDKDDPRSHRIVLPSGSlfflRVVHGRKGR-SDEGVYV 79

                ....*....
gi 49523315 413 CIARNEAGV 421
Cdd:cd07693  80 CVAHNSLGE 88

Second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor_like-1(FGFRL1); member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor like-1(FGFRL1). FGFRL1 is comprised of a signal peptide, three extracellular Ig-like modules, a transmembrane segment, and a short intracellular domain. FGFRL1 is expressed preferentially in skeletal tissues. Similar to FGF receptors, the expressed protein interacts specifically with heparin and with FGF2. FGFRL1 does not have a protein tyrosine kinase domain at its C-terminus; neither does its cytoplasmic domain appear to interact with a signaling partner. It has been suggested that FGFRL1 may not have any direct signaling function, but instead acts as a decoy receptor trapping FGFs and preventing them from binding other receptors.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 49523315 351 AREPGVTASLRCHAEGIPDPQLGWLKNGIDITPKL-----SKQLTLQangsevhISNVRYEDTGAYTCIARNEAG 420
Cdd:cd05856  15 ARPVGSSVRLKCVASGNPRPDITWLKDNKPLTPPEigenkKKKWTLS-------LKNLKPEDSGKYTCHVSNRAG 82

Second C-terminal immunoglobulin (Ig)-like domain of palladin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the C-terminal immunoglobulin (Ig)-like domain of palladin. Palladin belongs to the palladin-myotilin-myopalladin family. Proteins belonging to this family contain multiple Ig-like domains and function as scaffolds, modulating actin cytoskeleton. Palladin binds to alpha-actinin ezrin, vasodilator-stimulated phosphoprotein VASP, SPIN90 (also known as DIP or mDia interacting protein), and Src. Palladin also binds F-actin directly, via its Ig3 domain. Palladin is expressed as several alternatively spliced isoforms, having various combinations of Ig-like domains, in a cell-type-specific manner. It has been suggested that palladin's different Ig-like domains may be specialized for distinct functions. This group belongs to the I-set of IgSF domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 49523315 347 PESQAREPGVTASLRCHAEGIPDPQLGWLKNGIDITPKLSKQLTLQANGseVH---ISNVRYEDTGAYTCIARNEAG 420
Cdd:cd20990   7 PGDLTVQEGKLCRMDCKVSGLPTPDLSWQLDGKPIRPDSAHKMLVRENG--VHsliIEPVTSRDAGIYTCIATNRAG 81

agrin-responsive first immunoglobulin-like domains (Ig1) of the MuSK ectodomain; a member of the I-set of IgSF domains; The members here are composed of the first immunoglobulin-like domains (Ig1) of the Muscle-specific kinase (MuSK). MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the MuSK lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 49523315 252 DQRVSITAATVGQSAVLSCAIVGTLRPPIIWKRNNIVLNNLDL-EDINDFGDDgsLYITKVTTVHMGNYTCYA 323
Cdd:cd20970   6 PQPSFTVTAREGENATFMCRAEGSPEPEISWTRNGNLIIEFNTrYIVRENGTT--LTIRNIRRSDMGIYLCIA 76

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM); The members here are composed of the third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains, five fibronectin type III domains, a transmembrane region and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, or spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 49523315 355 GVTASLRCHAEGIPDPQLGWLK-NGiditPKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARNEAGVDEDISSLFVE 431
Cdd:cd05876  10 GQSLVLECIAEGLPTPTVKWLRpSG----PLPPDRVKYQNHNKTLQLLNVGESDDGEYVCLAENSLGSARHAYYVTVE 83

Seventh immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the seventh immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. This group is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 340 PPVIRVYPESQAREPGVTASLRCHAEGIPDPQLGWlKNGIDITP------KLSKQLTLQANGSeVHISNVRYEDTGAYTC 413
Cdd:cd20954   1 PPRWIVEPVDANVAAGQDVMLHCQADGFPTPTVTW-KKATGSTPgeykdlLYDPNVRILPNGT-LVFGHVQKENEGHYLC 78

                ....*..
gi 49523315 414 IARNEAG 420
Cdd:cd20954  79 EAKNGIG 85

Immunoglobulin domain; Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 49523315   354 PGVTASLRCHA-EGIPDPQLGWLKNG-IDITPKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARNEAGVD 422
Cdd:pfam00047  10 EGDSATLTCSAsTGSPGPDVTWSKEGgTLIESLKVKHDNGRTTQSSLLISNVTKEDAGTYTCVVNNPGGSA 80

agrin-responsive second immunoglobulin-like domains (Ig2) of the Muscle-specific kinase (MuSK) ectodomain; a member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin-like (Ig) domains of the Muscle-specific kinase (MuSK) ectodomain. MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the MuSK lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 49523315 355 GVTASLRCHAEGIPDPQLGWLKNgiDITPKLSKQLTLQANGSeVHISNVRYEDTGAYTCIARNEAGV 421
Cdd:cd20968  14 GLKAVLPCTTMGNPKPSVSWIKG--DDLIKENNRIAVLESGS-LRIHNVQKEDAGQYRCVAKNSLGI 77

Immunoglobulin (Ig)-like domain of human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) domains 2, 4, and 6, and similar domains; The members here are composed of the second, fourth, and sixth immunoglobulin (Ig)-like domains in human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) protein subfamily. The CEA family is a group of anchored or secreted glycoproteins expressed by epithelial cells, leukocytes, endothelial cells, and placenta. The CEA family is divided into the CEACAM and pregnancy-specific glycoprotein (PSG) subfamilies. This group represents the CEACAM subfamily. CEACAM1 has many important cellular functions; it is a cell adhesion molecule and a signaling molecule that regulates the growth of tumor cells, an angiogenic factor, and a receptor for bacterial and viral pathogens, including mouse hepatitis virus (MHV). In mice, four isoforms of CEACAM1 generated by alternative splicing have either two [D1, D4] or four [D1-D4] Ig-like domains on the cell surface.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 49523315 341 PVIRVyPESQAREPGVTASLRCHAEGiPDPQLGWLKNGIDItpKLSKQLTLQANGSEVHISNVRYEDTGAYTCIARNEAG 420
Cdd:cd05740   2 PFISS-NNSNPVEDKDAVTLTCEPET-QNTSYLWWFNGQSL--PVTPRLTLSNGNRTLTLLNVTREDAGAYQCEISNPVS 77