EF-hand, calcium binding motif; A diverse superfamily of calcium sensors and calcium signal modulators; most examples in this alignment model have 2 active canonical EF hands. Ca2+ binding induces a conformational change in the EF-hand motif, leading to the activation or inactivation of target proteins. EF-hands tend to occur in pairs or higher copy numbers.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 24585851  90 ELKEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDADGSGTVDFDEFMQVMT 152
Cdd:cd00051   1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 63

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 24585851    89 NELKEAFRVYDKEGKGYLTVATLRGILH--ELDDKLSNQDLDMIIEEIDADGSGTVDFDEFMQVMT 152
Cdd:pfam13499   2 EKLKEAFKLLDSDGDGYLDVEELKKLLRklEEGEPLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

XopAW family type III secretion system calcium-binding effector;

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 24585851   88 QNELKEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDADGSGTVDFDEFMQVMT 152
Cdd:NF041410  26 QQFQKQLFAKLDSDGDGSVSQDELSSALSSKSDDGSLIDLSELFSDLDSDGDGSLSSDELAAAAP 90

centrin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851    5 EYDKEQLRILRNAFKAFDHDGAGSIEHADVSSILEILGQKLEPPAVKALIKEVDKGTTGKLDFSQFCKLAARFIEVEEDv 84
Cdd:PTZ00183  10 GLTEDQKKEIREAFDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFLDIMTKKLGERDP- 88

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 24585851   85 galQNELKEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDADGSGTVDFDEFMQVMT 152
Cdd:PTZ00183  89 ---REEILKAFRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDGEISEEEFYRIMK 153

Ca2+-binding protein, EF-hand superfamily [Signal transduction mechanisms];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851   9 EQLRILRNAFKAFDHDGAGSIEHADVSSILEilgqklepPAVKALIKEVDKGTTGKLDFSQFCKLAARFIEveedvGALQ 88
Cdd:COG5126   2 LQRRKLDRRFDLLDADGDGVLERDDFEALFR--------RLWATLFSEADTDGDGRISREEFVAGMESLFE-----ATVE 68

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 24585851  89 NELKEAFRVYDKEGKGYLTVATLRGILHELDdkLSNQDLDMIIEEIDADGSGTVDFDEFMQVMTG 153
Cdd:COG5126  69 PFARAAFDLLDTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAVRD 131

Penta-EF hand, calcium binding motifs, found in Group I PEF proteins; The family corresponds to Group I PEF proteins that have been found not only in higher animals but also in lower animals, plants, fungi and protists. Group I PEF proteins include apoptosis-linked gene 2 protein (ALG-2), peflin and similar proteins. ALG-2, also termed programmed cell death protein 6 (PDCD6), is a widely expressed calcium-binding modulator protein associated with cell proliferation and death, as well as cell survival. It forms a homodimer in the cell or a heterodimer with its closest paralog peflin. Among the PEF proteins, ALG-2 can bind three Ca2+ ions through its EF1, EF3, and EF5 hands, where it is unique in that its EF5 hand binds Ca2+ ion in a canonical coordination. Peflin is a ubiquitously expressed 30-kD PEF protein containing five EF-hand motifs in its C-terminal domain and a longer N-terminal hydrophobic domain (NHB domain) than any other member of the PEF family. The NHB domain harbors nine repeats of a nonapeptide (A/PPGGPYGGP). Peflin may modulate the function of ALG-2 in Ca2+ signaling. It exists only as a heterodimer with ALG-2, and binds two Ca2+ ions through its EF1 and EF3 hands. Its additional EF5 hand is unpaired and does not bind Ca2+ ion but mediates the heterodimerization with ALG-2. The dissociation of heterodimer occurs in the presence of Ca2+.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  14 LRNAFKAFDHDGAGSIEHADVSSILeILG--QKLEPPAVKALIKEVDKGTTGKLDFSQFCKLAaRFIEveedvgalqnEL 91
Cdd:cd16180   2 LRRIFQAVDRDRSGRISAKELQRAL-SNGdwTPFSIETVRLMINMFDRDRSGTINFDEFVGLW-KYIQ----------DW 69

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 24585851  92 KEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDADGSGTVDFDEFMQVMT 152
Cdd:cd16180  70 RRLFRRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACV 130

The penta-EF hand (PEF) family; The penta-EF hand (PEF) family contains a group of five EF-hand calcium-binding proteins, including several classical calpain large catalytic subunits (CAPN1, 2, 3, 8, 9, 11, 12, 13, 14), two calpain small subunits (CAPNS1 and CAPNS2), as well as non-calpain PEF proteins, ALG-2 (apoptosis-linked gene 2, also termed programmed cell death protein 6, PDCD6), peflin, sorcin, and grancalcin. Based on the sequence similarity of EF1 hand, ALG-2 and peflin have been classified into group I PEF proteins. Calcium-dependent protease calpain subfamily members, sorcin and grancalcin, are group II PEF proteins. Calpains (EC 3.4.22.17) are calcium-activated intracellular cysteine proteases that play important roles in the degradation or functional modulation in a variety of substrates. They have been implicated in a number of physiological processes such as cell cycle progression, remodeling of cytoskeletal-cell membrane attachments, signal transduction, gene expression and apoptosis. ALG-2 is a pro-apoptotic factor that forms a homodimer in the cell or a heterodimer with its closest paralog peflin through their EF5s. Peflin is a 30-kD PEF protein with a longer N-terminal hydrophobic domain than any other member of the PEF family, and it contains nine nonapeptide (A/PPGGPYGGP) repeats. It exists only as a heterodimer with ALG-2. The dissociation of heterodimer occurs in the presence of Ca2+. ALG-2 interacts with various proteins in a Ca2+-dependent manner. Sorcin (for soluble resistance-related calcium binding protein) is a soluble resistance-related calcium-binding protein that participates in the regulation of calcium homeostasis in cells. Grancalcin is a cytosolic Ca2+-binding protein specifically expressed in neutrophils and monocytes/macrophages. It plays a key role in leukocyte-specific functions that are responsible for host defense. Grancalcin can form a heterodimer together with sorcin. Members in this family contain five EF-hand motifs attached to an N-terminal region of variable length containing one or more short Gly/Pro-rich sequences. These proteins form homodimers or heterodimers through pairing between the 5th EF-hands from the two molecules. Unlike calmodulin, the PEF domains do not undergo major conformational changes upon binding Ca2+.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  14 LRNAFKAFDHDgAGSIEHADVSSILEILGQK-----LEPPAVKALIKEVDKGTTGKLDFSQFcklaarfieveEDVGALQ 88
Cdd:cd15897   2 LRNVFQAVAGD-DGEISATELQQALSNVGWThfdlgFSLETCRSMIAMMDRDHSGKLNFSEF-----------KGLWNYI 69

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 24585851  89 NELKEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDaDGSGTVDFDEFMQ 149
Cdd:cd15897  70 KAWQEIFRTYDTDGSGTIDSNELRQALSGAGYRLSEQTYDIIIRRYD-RGRGNIDFDDFIQ 129

centrin; Provisional

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 24585851   78 IEVEEDVgalQNELKEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDADGSGTVDFDEFMQVMT 152
Cdd:PTZ00183   9 PGLTEDQ---KKEIREAFDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFLDIMT 80

Penta-EF hand, calcium binding motifs, found in Drosophila melanogaster calpain-A (CalpA), calpain-B (CalpB), and similar proteins; The family contains two calpains that have been found in Drosophila, CalpA and CalpB. CalpA, also termed calcium-activated neutral proteinase A (CANP A), or calpain-A catalytic subunit, is a Drosophila calpain homolog specifically expressed in a few neurons in the central nervous system, in scattered endocrine cells in the midgut, and in blood cells. CalpB, also termed calcium-activated neutral proteinase B (CANP B), contains calpain-B catalytic subunit 1 and calpain-B catalytic subunit 2. Both CalpA and CalpB are closely related to that of vertebrate calpains, and they share similar domain architecture, which consists of four domains: the N-terminal domain I, the catalytic domain II carrying the three active site residues, Cys, His and Asn, the Ca2+-regulated phospholipid-binding domain III, and penta-EF-hand Ca2+-binding domain IV. Besides, CalpA and CalpB display some distinguishing structural features that are not found in mammalian typical calpains. CalpA harbors a 76 amino acid long hydrophobic stretch inserted in domain IV, which may be involved in membrane attachment of this enzyme. CalpB has an unusually long N-terminal tail of 224 amino acids, which belongs to the class of intrinsically unstructured proteins (IUP) and may become ordered upon binding to target protein(s). Moreover, they do not need small regulatory subunits for their catalytic activity, and their proteolytic function is not regulated by an intrinsic inhibitor as the Drosophila genome contains neither regulatory subunit nor calpastatin orthologs. As a result, they may exist as a monomer or perhaps as a homo- or heterodimer together with a second large subunit. Furthermore, both CalpA and CalpB are dispensable for viability and fertility and do not share vital functions during Drosophila development. Phosphatidylinositol 4,5-diphosphate, phosphatidylinositol 4-monophosphate, phosphatidylinositol, and phosphatidic acid can stimulate the activity and the rate of activation of CalpA, but not CalpB. Calpain A modulates Toll responses by limited Cactus/IkappaB proteolysis. CalpB directly interacts with talin, an important component of the focal adhesion complex, and functions as an important modulator in border cell migration within egg chambers, which may act via the digestion of talin. CalpB can be phosphorylated by cAMP-dependent protein kinase (protein kinase A, PKA; EC 2.7.11.11) at Ser240 and Ser845, as well as by mitogen-activated protein kinase (ERK1 and ERK2; EC 2.7.11.24) at Thr747. The activation of the ERK pathway by extracellular signals results in the phosphorylation and activation of calpain B. In Schneider cells (S2), calpain B was mainly in the cytoplasm and upon a rise in Ca2+ the enzyme adhered to intracellular membranes.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851   3 DGEYDKEQLR-ILRNAF-KAFDHDGAgSIEhadvssileilgqkleppAVKALIKEVDKGTTGKLDFSQFCKLaarfiev 80
Cdd:cd16196  13 DMEIDAYELQdILNTAFkKDFPFDGF-SLD------------------ACRSMVAMMDVDRSGKLGFEEFKKL------- 66

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 24585851  81 eedvgalQNEL---KEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIdADGSGTVDFDEFMQVMT 152
Cdd:cd16196  67 -------WEDLrswKRVFKLFDTDGSGSFSSFELRNALNSAGFRLSNATLNALVLRY-SNKDGRISFDDFIMCAV 133

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        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  14 LRNAFKAFDHDGAGSIEHADVSSILEILGQKLEPPAVKALIKEVDKGTTGKLDFSQFCKLAARFIEveedvgalQNELKE 93
Cdd:cd15898   2 LRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKSLTE--------RPELEP 73

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 24585851  94 AFRVYDKEGKGYLTVATLRGIL-HELDDKLSNQDLDMIIEEIDADGS-GTVDFDEF 147
Cdd:cd15898  74 IFKKYAGTNRDYMTLEEFIRFLrEEQGENVSEEECEELIEKYEPEREnRQLSFEGF 129

EF-hand, calcium binding motif, found in the hexa-EF hand proteins family; The hexa-EF hand proteins family, also named the calbindin sub-family, contains a group of six EF-hand Ca2+-binding proteins, including calretinin (CR, also termed 29 kDa calbindin), calbindin D28K (CB, also termed vitamin D-dependent calcium-binding protein, avian-type), and secretagogin (SCGN). CR is a cytosolic hexa-EF-hand calcium-binding protein predominantly expressed in a variety of normal and tumorigenic t-specific neurons of the central and peripheral nervous system. It is a multifunctional protein implicated in many biological processes, including cell proliferation, differentiation, and cell death. CB is highly expressed in brain tissue. It is a strong calcium-binding and buffering protein responsible for preventing a neuronal death as well as maintaining and controlling calcium homeostasis. SCGN is a six EF-hand calcium-binding protein expressed in neuroendocrine, pancreatic endocrine and retinal cells. It plays a crucial role in cell apoptosis, receptor signaling and differentiation. It is also involved in vesicle secretion through binding to various proteins, including interacts with SNAP25, SNAP23, DOC2alpha, ARFGAP2, rootletin, KIF5B, beta-tubulin, DDAH-2, ATP-synthase and myeloid leukemia factor 2. SCGN functions as a Ca2+ sensor/coincidence detector modulating vesicular exocytosis of neurotransmitters, neuropeptides or hormones. Although the family members share a significant amount of secondary sequence homology, they display altered structural and biochemical characteristics, and operate in distinct fashions. CB contains six EF-hand motifs in a single globular domain, where EF-hands 1, 3, 4, 5 bind four calcium ions. CR contains six EF-hand motifs within two independent domains, CR I-II and CR III-VI. They harbor two and four EF-hand motifs, respectively. The first 5 EF-hand motifs are capable of binding calcium ions, while the EF-hand 6 is inactive. SCGN consists of the three globular domains each of which contains a pair of EF-hand motifs. Human SCGN simultaneously binds four calcium ions through its EF-hands 3, 4, 5 and 6 in one high affinity and three low affinity calcium-binding sites. In contrast, SCGNs in other lower eukaryotes, such as D. rerio, X. laevis, M. domestica, G. gallus, O. anatinus, are fully competent in terms of six calcium-binding.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  17 AFKAFDHDGAGSIEHADVSSILEILGQKLEPPA--------VKALIKEVDKGTTGKLDFSQFCKL---AARFIEVEEDVG 85
Cdd:cd15902  95 IWRKYDTDGSGFIEAKELKGFLKDLLLKNKKHVsppkldeyTKLILKEFDANKDGKLELDEMAKLlpvQENFLLKFQILG 174

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 24585851  86 AL---QNELKEAFRVYDKEGKGYLTVATLRGILHEL----DDKLSNQDLD----MIIEEIDADGSGTVDFDE 146
Cdd:cd15902 175 AMdltKEDFEKVFEHYDKDNNGVIEGNELDALLKDLleknKADIDKPDLEnfrdAILRACDKNKDGKIQKTE 246

Penta-EF hand, calcium binding motifs, found in sorcin, grancalcin, and similar proteins; The family corresponds to the second group of penta-EF hand (PEF) proteins that includes sorcin, grancalcin, and similar proteins. Sorcin, also termed 22 kDa Ca2+-binding protein, CP-22, or V19, is a soluble resistance-related calcium-binding protein that is expressed in normal mammalian tissues, such as the liver, lungs and heart. It contains a flexible glycine and proline-rich N-terminal extension and five EF-hand motifs that associate with membranes in a calcium-dependent manner. It may harbor three potential Ca2+ binding sites through its EF1, EF2 and EF3 hands. However, binding of only two Ca2+/monomer suffices to trigger the conformational change that exposes hydrophobic regions and leads to interaction with the respective targets. Sorcin forms homodimers through the association of the unpaired EF5 hand. Among the PEF proteins, sorcin is unique in that it contains potential phosphorylation sites by cAMP-dependent protein kinase (PKA), and it can form a tetramer at slightly acid pH values although remaining a stable dimer at neutral pH. Grancalcin (GCA) is a cytosolic Ca2+-binding protein specifically expressed in neutrophils and monocytes/macrophages. It can strongly interact with sorcin to form a heterodimer and further modulate the function of sorcin. GCA exists as homodimers in solution. It contains five EF-hand motifs attached to an N-terminal region of an approximately 50 residue-long segment rich in glycines and prolines. In contrast with sorcin, GCA binds two Ca2+ ions through its EF1 and EF3 hands.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  15 RNAFKAFDHDGAGSIEHADVSSILEILGQKLEPPAVKALIKEVdkGTTGKLDFSQFCKLAARFieveedvgalqNELKEA 94
Cdd:cd16181  73 KTTFMQYDRDRSGTVEPQELQQAIRSFGYNLSPQALNVIVKRY--SKNGRITFDDFVACAVRL-----------RALTDR 139

                        90
                ....*....|...
gi 24585851  95 FRVYDKEGKGYLT 107
Cdd:cd16181 140 FRRRDTQQNGTAT 152

EF-hand, calcium binding motif, found in homologs of mammalian apoptosis-linked gene 2 protein (ALG-2); The family includes some homologs of mammalian apoptosis-linked gene 2 protein (ALG-2) mainly found in lower eukaryotes, such as a parasitic protist Leishmarua major and a cellular slime mold Dictyostelium discoideum. These homologs contains five EF-hand motifs. Due to the presence of unfavorable residues at the Ca2+-coordinating positions, their non-canonical EF4 and EF5 hands may not bind Ca2+. Two Dictyostelium PEF proteins are the prototypes of this family. They may bind to cytoskeletal proteins and/or signal-transducing proteins localized to detergent-resistant membranes named lipid rafts, and occur as monomers or weak homo- or heterodimers like ALG-2. They can serve as a mediator for Ca2+ signaling-related Dictyostehum programmed cell death (PCD).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  14 LRNAFKAFDHDGAGSIEHADVSSILEILGQKLEPPAVKALIKEVDKGTTGKLDFSQFCKLAaRFIeveedvgalqNELKE 93
Cdd:cd16185   2 LRQWFRAVDRDRSGSIDVNELQKALAGGGLLFSLATAEKLIRMFDRDGNGTIDFEEFAALH-QFL----------SNMQN 70

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*
gi 24585851  94 AFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDADGSGTVDFDEFM 148
Cdd:cd16185  71 GFEQRDTSRSGRLDANEVHEALAASGFQLDPPAFQALFRKFDPDRGGSLGFDDYI 125

EF-hand domain pair;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 24585851   102 GKGYLTVATLRGILHELDDK-LSNQDLDMIIEEIDADGSGTVDFDEFMQVMT 152
Cdd:pfam13833   1 EKGVITREELKRALALLGLKdLSEDEVDILFREFDTDGDGYISFDEFCVLLE 52

EF-hand, calcium binding motif, found in the hexa-EF hand proteins family; The hexa-EF hand proteins family, also named the calbindin sub-family, contains a group of six EF-hand Ca2+-binding proteins, including calretinin (CR, also termed 29 kDa calbindin), calbindin D28K (CB, also termed vitamin D-dependent calcium-binding protein, avian-type), and secretagogin (SCGN). CR is a cytosolic hexa-EF-hand calcium-binding protein predominantly expressed in a variety of normal and tumorigenic t-specific neurons of the central and peripheral nervous system. It is a multifunctional protein implicated in many biological processes, including cell proliferation, differentiation, and cell death. CB is highly expressed in brain tissue. It is a strong calcium-binding and buffering protein responsible for preventing a neuronal death as well as maintaining and controlling calcium homeostasis. SCGN is a six EF-hand calcium-binding protein expressed in neuroendocrine, pancreatic endocrine and retinal cells. It plays a crucial role in cell apoptosis, receptor signaling and differentiation. It is also involved in vesicle secretion through binding to various proteins, including interacts with SNAP25, SNAP23, DOC2alpha, ARFGAP2, rootletin, KIF5B, beta-tubulin, DDAH-2, ATP-synthase and myeloid leukemia factor 2. SCGN functions as a Ca2+ sensor/coincidence detector modulating vesicular exocytosis of neurotransmitters, neuropeptides or hormones. Although the family members share a significant amount of secondary sequence homology, they display altered structural and biochemical characteristics, and operate in distinct fashions. CB contains six EF-hand motifs in a single globular domain, where EF-hands 1, 3, 4, 5 bind four calcium ions. CR contains six EF-hand motifs within two independent domains, CR I-II and CR III-VI. They harbor two and four EF-hand motifs, respectively. The first 5 EF-hand motifs are capable of binding calcium ions, while the EF-hand 6 is inactive. SCGN consists of the three globular domains each of which contains a pair of EF-hand motifs. Human SCGN simultaneously binds four calcium ions through its EF-hands 3, 4, 5 and 6 in one high affinity and three low affinity calcium-binding sites. In contrast, SCGNs in other lower eukaryotes, such as D. rerio, X. laevis, M. domestica, G. gallus, O. anatinus, are fully competent in terms of six calcium-binding.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  18 FKAFDHDGAGSIEHADVSSILEILGQKLEPPA---------VKALIKEVDKGTTGKLDFSQFCKL---AARFIEVEEDVG 85
Cdd:cd15902   5 WMHFDADGNGYIEGKELDSFLRELLKALNGKDktddevaekKKEFMEKYDENEDGKIEIRELANIlptEENFLLLFRREQ 84

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 24585851  86 ALQN--ELKEAFRVYDKEGKGYLTVATLRGILHEL--------DDKLSNQDLDMIIEEIDADGSGTVDFDEFM 148
Cdd:cd15902  85 PLISsvEFMKIWRKYDTDGSGFIEAKELKGFLKDLllknkkhvSPPKLDEYTKLILKEFDANKDGKLELDEMA 157

Eps15 homology domain; Pair of EF hand motifs that recognise proteins containing Asn-Pro-Phe (NPF) sequences.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|...
gi 24585851     95 FRVYDKEGKGYLTVATLRGILheLDDKLSNQDLDMIIEEIDADGSGTVDFDEF 147
Cdd:smart00027  16 FRSLDKNQDGTVTGAQAKPIL--LKSGLPQTLLAKIWNLADIDNDGELDKDEF 66

EF-hand, calcium binding motif, found in apoptosis-linked gene 2 protein (ALG-2) and similar proteins; ALG-2, also termed programmed cell death protein 6 (PDCD6), or probable calcium-binding protein ALG-2, is one of the prototypic members of the penta EF-hand protein family. It is a widely expressed calcium-binding modulator protein associated with cell proliferation and death, as well as cell survival. ALG-2 acts as a pro-apoptotic factor participating in T cell receptor-, Fas-, and glucocorticoid-induced programmed cell death, and also serves as a useful molecular marker for the prognosis of cancers. Moreover, ALG-2 functions as a calcium ion sensor at endoplasmic reticulum (ER) exit sites, and modulates ER-stress-stimulated cell death and neuronal apoptosis during organ formation. Furthermore, ALG-2 can mediate the pro-apoptotic activity of cisplatin or tumor necrosis factor alpha (TNFalpha) through the down-regulation of nuclear factor-kappaB (NF-kappaB) expression. It also inhibits angiogenesis through PI3K/mTOR/p70S6K pathway by interacting of vascular endothelial growth factor receptor-2 (VEGFR-2). In addition, nuclear ALG-2 may participate in the post-transcriptional regulation of Inositol Trisphosphate Receptor Type 1 (IP3R1) pre-mRNA at least in part by interacting with CHERP (Ca2+ homeostasis endoplasmic reticulum protein) calcium-dependently. ALG-2 contains five serially repeated EF-hand motifs and interacts with various proteins, including ALG-2-interacting protein X (Alix), Fas, annexin XI, death-associated protein kinase 1 (DAPk1), Tumor susceptibility gene 101 (TSG101), Sec31A, phospholipid scramblase 3 (PLSCR3), the P-body component PATL1, and endosomal sorting complex required for transport (ESCRT)-III-related protein IST1, in a calcium-dependent manner. It forms a homodimer in the cell or a heterodimer with its closest paralog peflin. Among the PEF proteins, ALG-2 can bind three Ca2+ ions through its EF1, EF3, and EF5 hands, where it is unique in that its EF5 hand binds Ca2+ ion in a canonical coordination.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  15 RNAFKAFDHDGAGSIEHADVSSILEILGQKLEPPAVKALIKEVDKGTTGKL---DFSQFCKLaarfieveedvgaLQNeL 91
Cdd:cd16183  70 QNCFRSFDRDNSGNIDKNELKQALTSFGYRLSDQFYDILVRKFDRQGRGTIafdDFIQCCVV-------------LQT-L 135

                        90
                ....*....|....*..
gi 24585851  92 KEAFRVYDKEGKGYLTV 108
Cdd:cd16183 136 TDSFRRYDTDQDGWIQI 152

EF-hand motif found in phosphoinositide phospholipase C eta 2 (PI-PLC-eta2); PI-PLC-eta2, also termed 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase eta-2, or phosphoinositide phospholipase C-like 4, or phospholipase C-like protein 4 (PLC-L4), or phospholipase C-eta-2 (PLC-eta2), is a neuron-specific PI-PLC that is most abundant in the brain, particularly in the hippocampus, habenula, olfactory bulb, cerebellum, and throughout the cerebral cortex. It is also expressed in the pituitary gland, pineal gland, retina, and lung, as well as in neuroendocrine cells. PI-PLC-eta2 has been implicated in the regulation of neuronal differentiation/maturation. It is required for retinoic acid-stimulated neurite growth. It may also in part function downstream of G-protein-coupled receptors and play an important role in the formation and maintenance of the neuronal network in the postnatal brain. Moreover, PI-PLC-eta2 acts as a Ca2+ sensor that shows a canonical EF-loop directing Ca2+-sensitivity and thus can amplify transient Ca2+ signals. Its activation can be triggered either by intracellular calcium mobilization or by G beta-gamma signaling. PI-PLC-eta2 contains an N-terminal pleckstrin homology (PH) domain, four atypical EF-hand motifs, a PLC catalytic core domain, a C2 domain, and a unique C-terminal tail that terminates with a PDZ-binding motif, a potential interaction site for other signaling proteins. The PLC catalytic core domain is a TIM barrel with two highly conserved regions (X and Y) split by a highly degenerate linker sequence. The C-terminal tail harbors a number of proline-rich motifs which may interact with SH3 (Src homology 3) domain-containing proteins, as well as many serine/threonine residues, suggesting possible regulation of interactions by protein kinases/phosphatases.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 24585851  91 LKEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDA-DGSGTVDFDEF 147
Cdd:cd16221   2 LKQTFDEADKNGDGSLSIGEVLQLLHKLNVNLPRQKVKQMFKEADTdDNQGTLGFEEF 59

EF-hand motif found in phosphoinositide phospholipase C eta (PI-PLC-eta); PI-PLC-eta isozymes represent a class of neuron-specific metazoan PI-PLCs that are most abundant in the brain, particularly in the hippocampus, habenula, olfactory bulb, cerebellum, and throughout the cerebral cortex. They are phosphatidylinositol 4,5-bisphosphate-hydrolyzing enzymes that are more sensitive to Ca2+ than other PI-PLC isozymes. They function as calcium sensors activated by small increases in intracellular calcium concentrations. They are also activated through G-protein-coupled receptor (GPCR) stimulation, and further mediate GPCR signalling pathways. PI-PLC-eta isozymes contain an N-terminal pleckstrin homology (PH) domain, four atypical EF-hand motifs, a PLC catalytic core domain, a C2 domain, and a unique C-terminal tail that terminates with a PDZ-binding motif, a potential interaction site for other signaling proteins. The PLC catalytic core domain is a TIM barrel with two highly conserved regions (X and Y) split by a highly degenerate linker sequence. The C-terminal tail harbors a number of proline-rich motifs which may interact with SH3 (Src homology 3) domain-containing proteins, as well as many serine/threonine residues, suggesting possible regulation of interactions by protein kinases/phosphatases. There are two PI-PLC-eta isozymes (1-2). Aside from the PI-PLC-eta isozymes identified in mammals, their eukaryotic homologs are also present in this family.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  91 LKEAFRVYDKEGKGYLTVATLRGILHELDDKLSNQDLDMIIEEIDADGS-GTVDFDEFMQ 149
Cdd:cd16205   2 LKQTFEEADKNGDGLLSIGEILQLMHKLNVNLPRRKVRQMFKEADTDDNqGTLDFEEFCA 61

EF-hand, calcium binding motif, found in calbindin (CB); CB, also termed calbindin D28, or D-28K, or avian-type vitamin D-dependent calcium-binding protein, is a unique intracellular calcium binding protein that functions as both a calcium sensor and buffer in eukaryotic cells, which undergoes a conformational change upon calcium binding and protects cells against insults of high intracellular calcium concentration. CB is highly expressed in brain and sensory neurons. It plays essential roles in neural functioning, altering synaptic interactions in the hippocampus, modulating calcium channel activity, calcium transients, and intrinsic neuronal firing activity. It prevents a neuronal death, as well as maintains and controls calcium homeostasis. CB also modulates the activity of proteins participating in the development of neurodegenerative disorders such as Alzheimer's disease, Huntington's disease, and bipolar disorder. Moreover, CB interacts with Ran-binding protein M, a protein known to involve in microtubule function. It also interacts with alkaline phosphatase and myo-inositol monophosphatase, as well as caspase 3, an enzyme that plays an important role in the regulation of apoptosis. CB contains six EF-hand motifs in a single globular domain, where EF-hands 1, 3, 4, 5 bind four calcium ions with high affinity.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  17 AFKAFDHDGAGSIEHADVSSILEILGQKLEPPA--------VKALIKEVDKGTTGKLDFSQFcklaARFIEVEED----- 83
Cdd:cd16176  90 TWRKYDADHSGFIEADELKSFLKDLLKKANKPFdeskleeyTHTMLKMFDSNNDGKLGLTEM----ARLLPVQENfllkf 165

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*...
gi 24585851  84 --VGALQNELKEAFRVYDKEGKGYLTVATLRGILHELDDKlSNQDLDM 129
Cdd:cd16176 166 qgVKMCGKEFNKIFELYDQDGNGYIDENELDALLKDLCEK-NKKDLDI 212

Penta-EF hand, calcium binding motifs, found in grancalcin; Grancalcin (GCA) is a cytosolic Ca2+-binding protein specifically expressed in neutrophils and monocytes/macrophages. It displays a Ca2+-dependent translocation to granules and plasma membrane upon neutrophil activation, suggesting roles in granule-membrane fusion and degranulation of neutrophils. It may also play a role in the regulation of vesicle/granule exocytosis through the reversible binding of secretory vesicles and plasma membranes upon the presence of calcium. Moreover, GCA is involved in inflammation, as well as in the process of adhesion of neutrophils to fibronectin. It plays a key role in leukocyte-specific functions that are responsible for host defense, and affects the function of integrin receptors on immune cells through binding to L-plastin in the absence of calcium. Furthermore, GCA can strongly interact with sorcin to form a heterodimer, and further modulate the function of sorcin. GCA exists as homodimers in solution. It contains five EF-hand motifs attached to an N-terminal region of an approximately 50 residue-long segment rich in glycines and prolines. GCA binds two Ca2+ ions through its EF1 and EF3 hands.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  18 FKAFDHDGAGSIEHADVSSILEILGQKLEPPAVKALIKEVDKgtTGKLDFSQFCKLAARFieveedvgalqNELKEAFRV 97
Cdd:cd16186  76 FMTVDQDRSGTVEPHELRQAIGAMGYRLSPQTLTTIVKRYSK--NGRIYFDDYVACCVKL-----------RALTDFFRR 142

                ....*....
gi 24585851  98 YDKEGKGYL 106
Cdd:cd16186 143 RDHMQQGSV 151

EF-hand, calcium binding motif, found in calretinin (CR); CR, also termed 29 kDa calbindin, is a cytosolic hexa-EF-hand calcium-binding protein predominantly expressed in a variety of normal and tumorigenic t specific neurons of the central and peripheral nervous system. It possibly functions as a calcium buffer, calcium sensor, and apoptosis regulator, which may be implicated in many biological processes, including cell proliferation, differentiation, and cell death. CR contains six EF-hand motifs within two independent domains, CR I-II and CR III-VI. CR I-II consists of EF-hand motifs 1 and 2, and CR III-VI consists of EF-hand motifs 3-6. The first 5 EF-hand motifs are capable of binding calcium ions, while the EF-hand 6 is inactive. Thus, CR has two pairs of cooperative binding sites (I-II and III-IV), which display high affinity calcium-binding sites, and one independent calcium ion-binding site (V), which displays lower affinity binding.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  18 FKAFDHDGAGSIEHADVSSILEIL-----GQKLEPPA------VKALIKEVDKGTTGKLDFSQFcklaARFIEVEED--- 83
Cdd:cd16177   5 WKHFDADGNGYIEGKELENFFRELerarrGAGVDSKSanfgekMKEFMQKYDKNADGRIEMAEL----AQILPTEENfll 80

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851  84 -----VGAlQNELKEAFRVYDKEGKGYLTVATLRGILHEL--------DDKLSNQDLDMIIEEIDADGSGTVDFDEFMQV 150
Cdd:cd16177  81 cfrqhVGS-SSEFMEAWRKYDTDRSGYIEANELKGFLSDLlkkanrpyDEKKLQEYTQTILRMFDLNGDGKLGLSEMARL 159

                .
gi 24585851 151 M 151
Cdd:cd16177 160 L 160

EF-hand, calcium binding motif, found in calumenin, reticulocalbin-1 (RCN-1), reticulocalbin-3 (RCN-3), and similar proteins; The family corresponds to a group of six EF-hand Ca2+-binding proteins, including calumenin (also known as crocalbin or CBP-50), reticulocalbin-1 (RCN-1), reticulocalbin-3 (RCN-3), and similar proteins. Calumenin is an endo/sarcoplasmic reticulum (ER/SR) resident low-affinity Ca2+-binding protein that contains six EF-hand domains and a C-terminal SR retention signal His-Asp-Glu-Phe (HDEF) tetrapeptide. It functions as a novel regulator of SERCA2, and its expressional changes are tightly coupled with Ca2+-cycling of cardiomyocytes. It is also broadly involved in haemostasis and in the pathophysiology of thrombosis. Moreover, the extracellular calumenin acts as a suppressor of cell migration and tumor metastasis. RCN-1 is an endoplasmic reticulum resident Ca2+-binding protein with a carboxyl-terminal His-Asp-Glu-Leu (HDEL) tetrapeptide signal. It acts as a potential negative regulator of B-RAF activation and can negatively modulate cardiomyocyte hypertrophy by inhibition of the mitogen-activated protein kinase signalling cascade. It also plays a key role in the development of doxorubicin-associated resistance. RCN-3 is a putative six EF-hand Ca2+-binding protein that contains five RXXR (X is any amino acid) motifs and a C-terminal ER retrieval signal HDEL tetrapeptide. The RXXR motif represents the target sequence of subtilisin-like proprotein convertases (SPCs). RCN-3 is specifically bound to the paired basic amino-acid-cleaving enzyme-4 (PACE4) precursor protein and plays an important role in the biosynthesis of PACE4.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24585851   8 KEQLRILrnaFKAFDHDGAGSIEHADVSSILEILGQKLEPPAVKALIKEVDKGTTGKLDFSQFCKLAARFIEVEEDVGAL 87
Cdd:cd16226  34 KERLGII---VDKIDKNGDGFVTEEELKDWIKYVQKKYIREDVDRQWKEYDPNKDGKLSWEEYKKATYGFLDDEEEDDDL 110

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 24585851  88 QNELKEA-------FRVYDKEGKGYLTVATLRGILH-ELDDKLSNQDLDMIIEEIDADGSGTVDFDEFM 148
Cdd:cd16226 111 HESYKKMirrderrWKAADQDGDGKLTKEEFTAFLHpEEFPHMRDIVVQETLEDIDKNKDGFISLEEYI 179