calmodulin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15241500   33 FDLFDKNNDGFITVEELSQALSRLGLDADFSDLKSTVDSfIKPDKTG-LRFDDFAALHKTldesffggegSCCDGSPESD 111
Cdd:PTZ00184  17 FSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINE-VDADGNGtIDFPEFLTLMAR----------KMKDTDSEEE 85

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 15241500  112 LEEAFNVFDEDGDGFISAVELQKVLKKLGlpEAGEIEQVEKMIVSVDSNHDGRVDFFEFKNMM 174
Cdd:PTZ00184  86 IKEAFKVFDRDGNGFISAAELRHVMTNLG--EKLTDEEVDEMIREADVDGDGQINYEEFVKMM 146

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 15241500   109 ESDLEEAFNVFDEDGDGFISAVELQKVLKKLGLPEAGEIEQVEKMIVSVDSNHDGRVDFFEFKNMMQ 175
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRKLEEGEPLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

EF-hand, calcium binding motif; EF-hands are calcium-binding motifs that occur at least in pairs. Links between disease states and genes encoding EF-hands, particularly the S100 subclass, are emerging. Each motif consists of a 12 residue loop flanked on either side by a 12 residue alpha-helix. EF-hands undergo a conformational change unpon binding calcium ions.

                           10        20
                   ....*....|....*....|....*....
gi 15241500    111 DLEEAFNVFDEDGDGFISAVELQKVLKKL 139
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

calmodulin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15241500   33 FDLFDKNNDGFITVEELSQALSRLGLDADFSDLKSTVDSfIKPDKTG-LRFDDFAALHKTldesffggegSCCDGSPESD 111
Cdd:PTZ00184  17 FSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINE-VDADGNGtIDFPEFLTLMAR----------KMKDTDSEEE 85

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 15241500  112 LEEAFNVFDEDGDGFISAVELQKVLKKLGlpEAGEIEQVEKMIVSVDSNHDGRVDFFEFKNMM 174
Cdd:PTZ00184  86 IKEAFKVFDRDGNGFISAAELRHVMTNLG--EKLTDEEVDEMIREADVDGDGQINYEEFVKMM 146

centrin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15241500   33 FDLFDKNNDGFITVEELSQALSRLGLDADFSDLKSTVDSFIKPDKTGLRFDDF-AALHKTLDESFfggegsccdgsPESD 111
Cdd:PTZ00183  23 FDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFlDIMTKKLGERD-----------PREE 91

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 15241500  112 LEEAFNVFDEDGDGFISAVELQKVLKKLGlpEAGEIEQVEKMIVSVDSNHDGRVDFFEFKNMM 174
Cdd:PTZ00183  92 ILKAFRLFDDDKTGKISLKNLKRVAKELG--ETITDEELQEMIDEADRNGDGEISEEEFYRIM 152

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 15241500  28 RLHRVFDLFDKNNDGFITVEELSQALSrLGLDADFSDlkSTVDSFIK---PDKTG-LRFDDFAALHKTLDesffggegsc 103
Cdd:cd16180   1 ELRRIFQAVDRDRSGRISAKELQRALS-NGDWTPFSI--ETVRLMINmfdRDRSGtINFDEFVGLWKYIQ---------- 67

                        90       100       110
                ....*....|....*....|....*....|....*..
gi 15241500 104 cdgspesDLEEAFNVFDEDGDGFISAVELQKVLKKLG 140
Cdd:cd16180  68 -------DWRRLFRRFDRDRSGSIDFNELQNALSSFG 97

centrin; Provisional

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 15241500  109 ESDLEEAFNVFDEDGDGFISAVELQKVLKKLGLPEagEIEQVEKMIVSVDSNHDGRVDFFEFKNMM 174
Cdd:PTZ00183  16 KKEIREAFDLFDTDGSGTIDPKELKVAMRSLGFEP--KKEEIKQMIADVDKDGSGKIDFEEFLDIM 79

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 15241500 111 DLEEAFNVFDEDGDGFISAVELQKVLKKLGLPEAgeIEQVEKMIVSVDSNHDGRVDFFEFKNMMQ 175
Cdd:cd16185   1 ELRQWFRAVDRDRSGSIDVNELQKALAGGGLLFS--LATAEKLIRMFDRDGNGTIDFEEFAALHQ 63

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 15241500  28 RLHRVFDLFDKNNDGFITVEELSQALSRLGLDADFSDLKSTVDSFIKPDKTGLRFDDFAALHKTLDEsffggegsccdgs 107
Cdd:cd15898   1 WLRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKSLTE------------- 67

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 15241500 108 pESDLEEAFNVFDEDGDGFISAVELQKVLKKLGLPEAGEiEQVEKMIVSVDSN-HDGRVDFFEFKNMM 174
Cdd:cd15898  68 -RPELEPIFKKYAGTNRDYMTLEEFIRFLREEQGENVSE-EECEELIEKYEPErENRQLSFEGFTNFL 133

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 15241500    28 RLHRVFDLFDKNNDGFITVEELSQALSRLGLDADFSDLKstVDSFIK---PDKTG-LRFDDFAAL 88
Cdd:pfam13499   3 KLKEAFKLLDSDGDGYLDVEELKKLLRKLEEGEPLSDEE--VEELFKefdLDKDGrISFEEFLEL 65

EF-hand, calcium binding motif, found in uncharacterized calglandulin-like proteins; The family corresponds to a group of uncharacterized calglandulin-like proteins. Although their biological function remain unclear, they show high sequence similarity with human calglandulin-like protein GAGLP, which is an ortholog of calglandulin from the venom glands of Bothrops insularis snake. Both GAGLP and calglandulin are putative Ca2+-binding proteins with four EF-hand motifs. However, members in this family contain only three EF-hand motifs. In this point, they may belong to the parvalbumin-like EF-hand family, which is characterized by the presence of three consecutive EF-hand motifs (helix-loop-helix).

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 15241500 109 ESDLEEAFNVFDEDGDGFISAVELQKVLKKLglPEAGEI-----EQVEKMIVSVDSNHDGRVDFFEFKNMMQ 175
Cdd:cd16252  36 EEAIRKAFQMLDKDKSGFIEWNEIKYILSTV--PSSMPVaplsdEEAEAMIQAADTDGDGRIDFQEFSDMVK 105

EF-hand domain;

                          10        20        30
                  ....*....|....*....|....*....|
gi 15241500   111 DLEEAFNVFDEDGDGFISAVELQKVLKKLG 140
Cdd:pfam13405   1 ELREAFKLFDKDGDGKISLEELRKALRSLG 30

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 15241500  31 RVFDLFDKNNDGFITVEEL--------SQALSRLGLDADFSDLKSTVDSFIKPDKTG-LRFDDFAALHKTLDESFFGGEg 101
Cdd:cd15902   3 EVWMHFDADGNGYIEGKELdsflrellKALNGKDKTDDEVAEKKKEFMEKYDENEDGkIEIRELANILPTEENFLLLFR- 81

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 15241500 102 scCDGSPESDLE--EAFNVFDEDGDGFISAVELQKVLK------KLGLPEAGEIEQVEKMIVSVDSNHDGRVDFFEF 170
Cdd:cd15902  82 --REQPLISSVEfmKIWRKYDTDGSGFIEAKELKGFLKdlllknKKHVSPPKLDEYTKLILKEFDANKDGKLELDEM 156

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 15241500  31 RVFDLFDKNNDGFITVEELSQALSRLG--LDADFSDLksTVDSFIKPDKTGLRFDDF---AALHKTLDESF 96
Cdd:cd16183  71 NCFRSFDRDNSGNIDKNELKQALTSFGyrLSDQFYDI--LVRKFDRQGRGTIAFDDFiqcCVVLQTLTDSF 139

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
                ....*....|....*....|....*....|....*....|....*....|....
gi 15241500 123 GDGFISAVELQKVLKKLGLP---EAGEIEQVEKMIVSVDSNHDGRVDFFEFKNM 173
Cdd:cd15897  12 DDGEISATELQQALSNVGWThfdLGFSLETCRSMIAMMDRDHSGKLNFSEFKGL 65

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 15241500  30 HRVFDLFDKNNDGFITVEELSQALSRLGLDADFSDLKSTVDSFIKPDKTGLRFDDFAALHKTLDEsffggegsccdgspe 109
Cdd:cd16180  70 RRLFRRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACVTLKR--------------- 134

                        90
                ....*....|....*...
gi 15241500 110 sdLEEAFNVFDEDGDGFI 127
Cdd:cd16180 135 --LTDAFRKYDTNRTGYA 150

EF-hand, calcium binding motif; EF-hands are calcium-binding motifs that occur at least in pairs. Links between disease states and genes encoding EF-hands, particularly the S100 subclass, are emerging. Each motif consists of a 12 residue loop flanked on either side by a 12 residue alpha-helix. EF-hands undergo a conformational change unpon binding calcium ions.

                           10        20
                   ....*....|....*....|....*....
gi 15241500    111 DLEEAFNVFDEDGDGFISAVELQKVLKKL 139
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

EF-hand domain pair;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 15241500   123 GDGFISAVELQKVLKKLGLPEAGEiEQVEKMIVSVDSNHDGRVDFFEFKNMMQ 175
Cdd:pfam13833   1 EKGVITREELKRALALLGLKDLSE-DEVDILFREFDTDGDGYISFDEFCVLLE 52

EF-hand, calcium binding motif, found in peflin and similar proteins; Peflin, also termed penta-EF hand (PEF) protein with a long N-terminal hydrophobic domain, or penta-EF hand domain-containing protein 1, 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+. In lower vertebrates, peflin may interact with transient receptor potential N (TRPN1), suggesting a potential role of peflin in fast transducer channel adaptation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 15241500  32 VFDLFDKNNDGFITVEELSQALSRLG--LDADFSdlKSTVDSFIKPDKTGLRFDDF 85
Cdd:cd16184  72 VFQQFDRDRSGSIDENELHQALSQMGyrLSPQFV--QFLVSKYDPRARRSLTLDQF 125

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 15241500  17 FRLRSPSLNALRLHRVFDLFDKNNDGFITVEELSQALSRLGLDADFSDLKSTVDSFIK-------PDKTG-LRFDDFAAL 88
Cdd:cd15902  80 FRREQPLISSVEFMKIWRKYDTDGSGFIEAKELKGFLKDLLLKNKKHVSPPKLDEYTKlilkefdANKDGkLELDEMAKL 159

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15241500  89 HKTLDESFFGGEGSCCDGSPESDLEEAFNVFDEDGDGFISAVELQKVLKKLG-----LPEAGEIEQVEKMIVSV-DSNHD 162
Cdd:cd15902 160 LPVQENFLLKFQILGAMDLTKEDFEKVFEHYDKDNNGVIEGNELDALLKDLLeknkaDIDKPDLENFRDAILRAcDKNKD 239

                ...
gi 15241500 163 GRV 165
Cdd:cd15902 240 GKI 242

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.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15241500  32 VFDLFDKNNDGFIT-------VEELSQALSRLGLDADfSDLKSTVDSFIKPDKTGLRFDDFAALHKTLDES--FFGGEGS 102
Cdd:cd16176   4 IWHHYDNDGNGYIEgkelqsfIQELQQARKKAGLELS-DQMKAFVDQYGQSTDGKIGIVELAQILPTEENFllFFRQQLK 82

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 15241500 103 CCDgspesDLEEAFNVFDEDGDGFISAVELQKVLKKL------GLPEAGEIEQVEKMIVSVDSNHDGRVDFFEFKNMM 174
Cdd:cd16176  83 SSE-----EFMQTWRKYDADHSGFIEADELKSFLKDLlkkankPFDESKLEEYTHTMLKMFDSNNDGKLGLTEMARLL 155

EF hand;

                          10        20
                  ....*....|....*....|....*
gi 15241500   112 LEEAFNVFDEDGDGFISAVELQKVL 136
Cdd:pfam13202   1 LKDTFRQIDLNGDGKISKEELRRLL 25

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 15241500  28 RLHR-------VFDLFDKNNDGFITVEELSQALSRLGLDADFSDLKSTVDSFiKPDKTG-LRFDDFAAL 88
Cdd:cd16185  60 ALHQflsnmqnGFEQRDTSRSGRLDANEVHEALAASGFQLDPPAFQALFRKF-DPDRGGsLGFDDYIEL 127