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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206  79 FAQAFKLFDKDGNNTMNIKELGEAMRMLglnpteeeLLNMVNEYDVDGNGKIDFGEFCKMMKEMNKETDQELIRLAFKVF 158
Cdd:COG5126     7 LDRRFDLLDADGDGVLERDDFEALFRRL--------WATLFSEADTDGDGRISREEFVAGMESLFEATVEPFARAAFDLL 78

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1972267206 159 DKDGNGYITAQEFKHFMTTMGerFSEEEVDEIIREVDKDGDEQIDLDEFVNMVAP 213
Cdd:COG5126    79 DTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAVRD 131

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1972267206 151 IRLAFKVFDKDGNGYITAQEFKHFMTTMGER--FSEEEVDEIIREVDKDGDEQIDLDEFVNMV 211
Cdd:pfam13499   4 LKEAFKLLDSDGDGYLDVEELKKLLRKLEEGepLSDEEVEELFKEFDLDKDGRISFEEFLELY 66

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 1972267206  151 IRLAFKVFDKDGNGYITAQEFKHFMTTM 178
Cdd:smart00054   2 LKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

centrin; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206  70 EFTPEELQEFAQAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMM--KEMNKETD 147
Cdd:PTZ00183   10 GLTEDQKKEIREAFDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFLDIMtkKLGERDPR 89

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1972267206 148 QELIRlAFKVFDKDGNGYITAQEFKHFMTTMGERFSEEEVDEIIREVDKDGDEQIDLDEFVNM 210
Cdd:PTZ00183   90 EEILK-AFRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDGEISEEEFYRI 151

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 1972267206 151 IRLAFKVFDKDGNGYITAQEFKHFMTTMGERFSEEEVDEIIREVDKDGDEQIDLDEFVNMVA 212
Cdd:cd00051     2 LREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 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 1972267206  79 FAQAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMMKEMnkeTDQELIRLAFKVF 158
Cdd:cd15898     2 LRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKSL---TERPELEPIFKKY 78

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1972267206 159 DKDGNGYITAQEFKHFMT-TMGERFSEEEVDEIIREVDKDG-DEQIDLDEFVNM 210
Cdd:cd15898    79 AGTNRDYMTLEEFIRFLReEQGENVSEEECEELIEKYEPEReNRQLSFEGFTNF 132

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 1972267206  78 EFAQAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMMKEMNKetdqelIRLAFKV 157
Cdd:cd16185     1 ELRQWFRAVDRDRSGSIDVNELQKALAGGGLLFSLATAEKLIRMFDRDGNGTIDFEEFAALHQFLSN------MQNGFEQ 74

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1972267206 158 FDKDGNGYITAQEFKHFMTTMGERFSEEEVDEIIREVDKDGDEQIDLDEFVNMVA 212
Cdd:cd16185    75 RDTSRSGRLDANEVHEALAASGFQLDPPAFQALFRKFDPDRGGSLGFDDYIELCI 129

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1972267206 151 IRLAFKVFDKDGNGYITAQEFKHFMTTMGER--FSEEEVDEIIREVDKDGDEQIDLDEFVNMV 211
Cdd:pfam13499   4 LKEAFKLLDSDGDGYLDVEELKKLLRKLEEGepLSDEEVEELFKEFDLDKDGRISFEEFLELY 66

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 1972267206 114 ELLNMVNEYDVDGNGKIDFGEFCKMMKEMNKETDQELIRLAFKVFDKDGNGYITAQEFKHFMT 176
Cdd:cd00051     1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 63

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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 128 GKIDFGEFCKMMKE-MNKETDQELIRLAFKVFDKDGNGYITAQEFKHFMTTMGER-----FSEEEVDEIIREVDKDGDEQ 201
Cdd:cd16252    15 GSFNYSKFFEYMQKfQTSEQQEEAIRKAFQMLDKDKSGFIEWNEIKYILSTVPSSmpvapLSDEEAEAMIQAADTDGDGR 94

                          90
                  ....*....|
gi 1972267206 202 IDLDEFVNMV 211
Cdd:cd16252    95 IDFQEFSDMV 104

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 1972267206  67 DADEF---TPEELQE-FAQAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMM--- 139
Cdd:cd16226    21 EAKEFdqlTPEESKErLGIIVDKIDKNGDGFVTEEELKDWIKYVQKKYIREDVDRQWKEYDPNKDGKLSWEEYKKATygf 100

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 140 ------KEMNKETDQELIRLA---FKVFDKDGNGYITAQEFKHFMttmgerFSEEE-------VDEIIREVDKDGDEQID 203
Cdd:cd16226   101 lddeeeDDDLHESYKKMIRRDerrWKAADQDGDGKLTKEEFTAFL------HPEEFphmrdivVQETLEDIDKNKDGFIS 174

                         170       180
                  ....*....|....*....|
gi 1972267206 204 LDEFVNMVAPivSDGTKTDP 223
Cdd:cd16226   175 LEEYIGDMYR--DDDEEEDP 192

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 1972267206  79 FAQAFKLFDKDGNNTMNIKELGEAMRML-----GLNPTEEELLNMVNE----YDVDGNGKIDFGEFCKMMKemnkeTDQE 149
Cdd:cd15902     1 FMEVWMHFDADGNGYIEGKELDSFLRELlkalnGKDKTDDEVAEKKKEfmekYDENEDGKIEIRELANILP-----TEEN 75

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 150 LIRL---------------AFKVFDKDGNGYITAQEFKHFM--------TTMGERFSEEEVDEIIREVDKDGDEQIDLDE 206
Cdd:cd15902    76 FLLLfrreqplissvefmkIWRKYDTDGSGFIEAKELKGFLkdlllknkKHVSPPKLDEYTKLILKEFDANKDGKLELDE 155

                  ....
gi 1972267206 207 FVNM 210
Cdd:cd15902   156 MAKL 159

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 1972267206  69 DEFTP--EELQEFAQAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMMKEMNKET 146
Cdd:cd16180    57 DEFVGlwKYIQDWRRLFRRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACVTLKRLT 136

                          90       100       110
                  ....*....|....*....|....*....|
gi 1972267206 147 DqelirlAFKVFDKDGNGYITAQeFKHFMT 176
Cdd:cd16180   137 D------AFRKYDTNRTGYATIS-YEDFLT 159

calmodulin; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 139 MKEMNKETDQELIRLAFKVFDKDGNGYITAQEFKHFMTTMGERFSEEEVDEIIREVDKDGDEQIDLDEFVNMVAPIVSDG 218
Cdd:PTZ00184    1 MADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADGNGTIDFPEFLTLMARKMKDT 80

                  ....*...
gi 1972267206 219 TKTDPFLE 226
Cdd:PTZ00184   81 DSEEEIKE 88

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1972267206 112 EEELLNMVNEYDVDGNGKIDFGEFCKMMK--EMNKETDQELIRLAFKVFDKDGNGYITAQEFKHFMT 176
Cdd:pfam13499   1 EEKLKEAFKLLDSDGDGYLDVEELKKLLRklEEGEPLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

centrin; Provisional

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1972267206  77 QEFAQAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMMKEMN 143
Cdd:PTZ00183   90 EEILKAFRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDGEISEEEFYRIMKKTN 156

EF-hand, calcium binding motif, found in secretagogin (SCGN); 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 calcium sensor/coincidence detector modulating vesicular exocytosis of neurotransmitters, neuropeptides or hormones. It also serves as a calcium buffer in neurons. Thus, SCGN may be linked to the pathogenesis of neurological diseases such as Alzheimer's, and also acts as a serum marker of neuronal damage, or as a tumor biomarker. SCGN consists of the three globular domains each of which contains a pair of EF-hand motifs. All six EF hand motifs of SCGN in some eukaryotes, including D. rerio, X. laevis, M. domestica, G. gallus, O. anatinus, could potentially bind six calcium ions. In contrast, SCGNs from higher eukaryotes have at least one non-functional EF-hand motif due to the mutation(s) or deletions. For instance, the EF1 loop does not coordinate calcium ion due to the key residue asparagine replaced by lysine in SCGNs of many mammalian species. Moreover, the EF2 loop seems to be competent for calcium-binding in most mammalian SCGNs except for human and chimpanzee orthologs.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206  79 FAQAFKLFDKDGNNTMNIKELGE-----AMRMLGLNPTEEELLNMVNE-----YDVDGNGKIDFGEFCKMM--------- 139
Cdd:cd16178     1 FAEIWQHFDADESGYIEGKELDNffkdlLKKLGTKDTISADEVQDVKEcfmsaYDVTGDGRIQIQELANIIlpddenfll 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 140 ---KEMNKETDQELIRLaFKVFDKDGNGYITAQEFKHF----MTTMGERFSEEEVDE----IIREVDKDGDEQIDLDEFV 208
Cdd:cd16178    81 ffrREEPLDSSVEFMRI-WRKYDADSSGYISAAELKNFlrdlFLQHKKVITEDKLDEytdtMMKIFDKNKDGRLDLNDMA 159

                  ....
gi 1972267206 209 NMVA 212
Cdd:cd16178   160 RILA 163

EF-hand, calcium binding motif, found in reticulocalbin-2 (RCN2) mainly from protostomes; This family corresponds to a group of uncharacterized RCN2-like proteins, which are mainly found in protostomes. Although their biological function remains unclear, they show high sequence similarity with RCN2 (also known as E6BP or TCBP-49), which is an endoplasmic reticulum resident low-affinity Ca2+-binding protein that has been implicated in immunity, redox homeostasis, cell cycle regulation and coagulation. Members in this family contain six copies of the EF-hand Ca2+-binding motif, but may lack a C-terminal His-Asp-Glu-Leu (HDEL) tetrapeptide that is required for retention of RCN2 in the endoplasmic reticulum (ER).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206  72 TPEELQEFAQAFKLF---DKDGNNTMNIKEL------GEAMRMLGLnpteeELLNMVNEYDVDGNGKIDFGEFC-KMMKE 141
Cdd:cd16227   114 TEDDLKLLEDDKEMFeaaDLNKDGKLDKTEFsafqhpEEYPHMHPV-----LIEQTLRDKDKDNDGFISFQEFLgDRAGH 188

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1972267206 142 MNKETDQ-ELIRLAfKVFDKDGNGYITAQEFKHFMTTMGERFSEEEVDEIIREVDKDGDEQIDLDEFVN 209
Cdd:cd16227   189 EDKEWLLvEKDRFD-EDYDKDGDGKLDGEEILSWLVPDNEEIAEEEVDHLFASADDDHDDRLSFDEILD 256

EF-hand motif found in Saccharomyces cerevisiae phospholipase C-1 (ScPlc1p) and similar proteins; This family represents a group of putative phosphoinositide-specific phospholipase C (PI-PLC, EC 3.1.4.11) encoded by PLC1 genes from yeasts, which are homologs of the delta isoforms of mammalian PI-PLC in terms of overall sequence similarity and domain organization. Mammalian PI-PLC is a signaling enzyme that hydrolyzes 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 then phosphorylates other molecules, leading to altered cellular activity. Calcium is required for the catalysis. The prototype of this family is protein Plc1p (also termed 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase 1) encoded by PLC1 genes from Saccharomyces cerevisiae. ScPlc1p contains both highly conserved X- and Y- regions of PLC catalytic core domain, as well as a presumptive EF-hand like calcium binding motif. Experiments show that ScPlc1p displays calcium dependent catalytic properties with high similarity to those of the mammalian PLCs, and plays multiple roles in modulating the membrane/protein interactions in filamentation control. CaPlc1p encoded by CAPLC1 from the closely related yeast Candida albicans, an orthologue of S. cerevisiae Plc1p, is also included in this group. Like SCPlc1p, CaPlc1p has conserved presumptive catalytic domain, shows PLC activity when expressed in E. coli, and is involved in multiple cellular processes. There are two other gene copies of CAPLC1 in C. albicans, CAPLC2 (also named as PIPLC) and CAPLC3. Experiments show CaPlc1p is the only enzyme in C. albicans which functions as PLC. The biological functions of CAPLC2 and CAPLC3 gene products must be clearly different from CaPlc1p, but their exact roles remain unclear. Moreover, CAPLC2 and CAPLC3 gene products are more similar to extracellular bacterial PI-PLC than to the eukaryotic PI-PLC, and they are not included in this subfamily.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 104 RMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMMKEMNKETDQELIrlaFKVFDKDGNGYITAQEFKHFMTTM-GERF 182
Cdd:cd16207    29 RRLHINCSESYLRELFDKADTDKKGYLNFEEFQEFVKLLKRRKDIKAI---FKQLTKPGSDGLTLEEFLKFLRDVqKEDV 105

                          90       100       110
                  ....*....|....*....|....*....|.
gi 1972267206 183 SEEEVDEI----IREVDKDGDEQIDLDEFVN 209
Cdd:cd16207   106 DRETWEKIfekfARRIDDSDSLTMTLEGFTS 136

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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206  81 QAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGN-GKIDFGEFCKMMKEMNKETDQELIRLAFkvfd 159
Cdd:cd16205     4 QTFEEADKNGDGLLSIGEILQLMHKLNVNLPRRKVRQMFKEADTDDNqGTLDFEEFCAFYKMMSTRRELYLLLLSY---- 79

                          90
                  ....*....|....*...
gi 1972267206 160 KDGNGYITAQEFKHFMTT 177
Cdd:cd16205    80 SNKKDYLTLEDLARFLEV 97

EF-hand, calcium binding motif, found in alpha-parvalbumin; Alpha-parvalbumin is cytosolic Ca2+/Mg2+-binding protein expressed mainly in fast-twitch skeletal myofibrils, where it may act as a soluble relaxing factor facilitating the Ca2+-mediated relaxation phase. It is also expressed in rapidly firing neurons, particularly GABA-ergic neurons, and thus may confer protection against Ca2+ toxicity. The major role of alpha-parvalbumin is metal buffering and transport of Ca2+. It binds different metal cations, and exhibits very high affinity for Ca2+ and physiologically significant affinity for Mg2+. Alpha-parvalbumin is characterized by the presence of three consecutive EF-hand motifs (helix-loop-helix) called AB, CD, and EF, but only CD and EF can chelate metal ions, such as Ca2+ and Mg2+. Both metal ion-binding sites in alpha-parvalbumin are high-affinity sites. Additionally, in contrast to beta-parvalbumin, alpha-parvalbumin is less acidic and has an additional residue in the C-terminal helix.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 128 GKIDFGEFCKMMKEMNKETDQelIRLAFKVFDKDGNGYITAQEFKHFM---TTMGERFSEEEVDEIIREVDKDGDEQIDL 204
Cdd:cd16254    15 DSFDYKKFFEMVGLKKKSADD--VKKVFHILDKDKSGFIEEDELKFVLkgfSPDGRDLSDKETKALLAAGDKDGDGKIGI 92

                  ....*...
gi 1972267206 205 DEFVNMVA 212
Cdd:cd16254    93 DEFATLVA 100

EF-hand, calcium binding motif, found in beta-parvalbumin; Beta-parvalbumin, also termed Oncomodulin-1 (OM), is a small calcium-binding protein that is expressed in hepatomas, as well as in the blastocyst and the cytotrophoblasts of the placenta. It is also found to be expressed in the cochlear outer hair cells of the organ of Corti and frequently expressed in neoplasms. Mammalian beta-parvalbumin is secreted by activated macrophages and neutrophils. It may function as a tissue-specific Ca2+-dependent regulatory protein, and may also serve as a specialized cytosolic Ca2+ buffer. Beta-parvalbumin acts as a potent growth-promoting signal between the innate immune system and neurons in vivo. It has high and specific affinity for its receptor on retinal ganglion cells (RGC) and functions as the principal mediator of optic nerve regeneration. It exerts its effects in a cyclic adenosine monophosphate (cAMP)-dependent manner and can further elevate intracellular cAMP levels. Moreover, beta-parvalbumin is associated with efferent function and outer hair cell electromotility, and can identify different hair cell types in the mammalian inner ear. Beta-parvalbumin is characterized by the presence of three consecutive EF-hand motifs (helix-loop-helix) called AB, CD, and EF, but only CD and EF can chelate metal ions, such as Ca2+ and Mg2+. The EF site displays a high-affinity for Ca2+/Mg2+, and the CD site is a low-affinity Ca2+-specific site. In addition, beta-parvalbumin is distinguished from other parvalbumins by its unusually low isoelectric point (pI = 3.1) and sequence eccentricities (e.g., Y57-L58-D59 instead of F57-I58-E59).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 131 DFGEFCKMMKEMNKETDQelIRLAFKVFDKDGNGYITAQEFKHFMttmgERFS-------EEEVDEIIREVDKDGDEQID 203
Cdd:cd16255    18 NFKKFFATSGLSKKSADD--VKKVFEIIDQDKSGFIEEEELKLFL----QNFSsgareltDAETKAFLKAGDSDGDGKIG 91

                          90
                  ....*....|
gi 1972267206 204 LDEFVNMVAP 213
Cdd:cd16255    92 VEEFQALVKA 101

EF-hand motif found in phosphoinositide phospholipase C delta (PI-PLC-delta); PI-PLC-delta isozymes represent a class of metazoan PI-PLCs that are some of the most sensitive to calcium among all PLCs. Their activation is modulated by intracellular calcium ion concentration, phospholipids, polyamines, and other proteins, such as RhoAGAP. Like other PI-PLC isozymes, PI-PLC-delta isozymes contain 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 C-terminal C2 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. There are three PI-PLC-delta isozymes (1, 3 and 4). PI-PLC-delta1 is relatively well characterized. It is activated by high calcium levels generated by other PI-PLC family members, and therefore functions as a calcium amplifier within the cell. Different PI-PLC-delta isozymes have different tissue distribution and different subcellular locations. PI-PLC-delta1 is mostly a cytoplasmic protein, PI-PLC-delta3 is located in the membrane, and PI-PLC-delta4 is predominantly detected in the cell nucleus. PI-PLC-delta isozymes is evolutionarily conserved even in non-mammalian species, such as yeast, slime molds and plants.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206  81 QAFKLFDKDGNNTMNIKELGEAMRMLGLNPTEEELLNMVNEYDVDGNGKIDFGEFCKMMKEMNKEtdQELIRLaFKVFDK 160
Cdd:cd16202     4 DQFRKADKNGDGKLSFKECKKLLKKLNVKVDKDYAKKLFQEADTSGEDVLDEEEFVQFYNRLTKR--PEIEEL-FKKYSG 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*
gi 1972267206 161 DGnGYITAQEFKHFMTTMGER--FSEEEVDEIIR--EVDKDGDEQ 201
Cdd:cd16202    81 DD-EALTVEELRRFLQEEQKVkdVTLEWAEQLIEtyEPSEDLKAQ 124

EF-hand domain;

                          10        20
                  ....*....|....*....|....*....
gi 1972267206 151 IRLAFKVFDKDGNGYITAQEFKHFMTTMG 179
Cdd:pfam13405   2 LREAFKLFDKDGDGKISLEELRKALRSLG 30

S-100: S-100 domain, which represents the largest family within the superfamily of proteins carrying the Ca-binding EF-hand motif. Note that this S-100 hierarchy contains only S-100 EF-hand domains, other EF-hands have been modeled separately. S100 proteins are expressed exclusively in vertebrates, and are implicated in intracellular and extracellular regulatory activities. Intracellularly, S100 proteins act as Ca-signaling or Ca-buffering proteins. The most unusual characteristic of certain S100 proteins is their occurrence in extracellular space, where they act in a cytokine-like manner through RAGE, the receptor for advanced glycation products. Structural data suggest that many S100 members exist within cells as homo- or heterodimers and even oligomers; oligomerization contributes to their functional diversification. Upon binding calcium, most S100 proteins change conformation to a more open structure exposing a hydrophobic cleft. This hydrophobic surface represents the interaction site of S100 proteins with their target proteins. There is experimental evidence showing that many S100 proteins have multiple binding partners with diverse mode of interaction with different targets. In addition to S100 proteins (such as S100A1,-3,-4,-6,-7,-10,-11,and -13), this group includes the ''fused'' gene family, a group of calcium binding S100-related proteins. The ''fused'' gene family includes multifunctional epidermal differentiation proteins - profilaggrin, trichohyalin, repetin, hornerin, and cornulin; functionally these proteins are associated with keratin intermediate filaments and partially crosslinked to the cell envelope. These ''fused'' gene proteins contain N-terminal sequence with two Ca-binding EF-hands motif, which may be associated with calcium signaling in epidermal cells and autoprocessing in a calcium-dependent manner. In contrast to S100 proteins, "fused" gene family proteins contain an extraordinary high number of almost perfect peptide repeats with regular array of polar and charged residues similar to many known cell envelope proteins.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206 159 DKDGNGY-ITAQEFKHFMTT-----MGERFSEEEVDEIIREVDKDGDEQIDLDEFVNMVA 212
Cdd:cd00213    19 GKEGDKDtLSKKELKELLETelpnfLKNQKDPEAVDKIMKDLDVNKDGKVDFQEFLVLIG 78

EF-hand, calcium binding motif, found in mitochondrial calcium uptake proteins MICU1, MICU2, MICU3, and similar proteins; This family includes mitochondrial calcium uptake protein MICU1 and its two additional paralogs, MICU2 and MICU3. MICU1 localizes to the inner mitochondrial membrane (IMM). It functions as a gatekeeper of the mitochondrial calcium uniporter (MCU) and regulates MCU-mediated mitochondrial Ca2+ uptake, which is essential for maintaining mitochondrial homoeostasis. MICU1 and MICU2 are physically associated within the uniporter complex and are co-expressed across all tissues. They may play non-redundant roles in the regulation of the mitochondrial calcium uniporter. At present, the precise molecular function of MICU2 and MICU3 remain unclear. MICU2 may play possible roles in Ca2+ sensing and regulation of MCU, calcium buffering with a secondary impact on transport or assembly and stabilization of MCU. MICU3 likely has a role in mitochondrial calcium handling. All members in this family contains an N-terminal mitochondrial targeting sequence (MTS) as well as two evolutionarily conserved canonical Ca2+-binding EF-hands separated by a long stretch of residues predicted to form alpha-helices.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1972267206  79 FAQAFKLFDKDGNNTMNIKE---LGEAMR---MLGLNPTEEELLNMVNEYDV----------DGNGKIDFGEFCKMMKEM 142
Cdd:cd15900     2 FEIAFKMFDLDGDGELDKEEfnkVQSIIRsqtSVGQRHRDHTNGESTKLGMNstlaryffgkDGKQKLSIEKFLEFQENL 81

                          90       100       110       120       130       140
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1972267206 143 NKETDQELIRLAFKVFdkdGNGYITAQEFKHFM-TTMGERFSEEEVDEIIREVDKDGDEQIDLDEFV 208
Cdd:cd15900    82 QEEIDDVDTALTFYHL---AGASIDRKTFKRAAkVVAGVELSDHVVDVVFTIFDEDGDGILSHKEFI 145

EF-hand motif found in phosphoinositide phospholipase C delta (PI-PLC-delta); PI-PLC-delta isozymes represent a class of metazoan PI-PLCs that are some of the most sensitive to calcium among all PLCs. Their activation is modulated by intracellular calcium ion concentration, phospholipids, polyamines, and other proteins, such as RhoAGAP. Like other PI-PLC isozymes, PI-PLC-delta isozymes contain 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 C-terminal C2 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. There are three PI-PLC-delta isozymes (1, 3 and 4). PI-PLC-delta1 is relatively well characterized. It is activated by high calcium levels generated by other PI-PLC family members, and therefore functions as a calcium amplifier within the cell. Different PI-PLC-delta isozymes have different tissue distribution and different subcellular locations. PI-PLC-delta1 is mostly a cytoplasmic protein, PI-PLC-delta3 is located in the membrane, and PI-PLC-delta4 is predominantly detected in the cell nucleus. PI-PLC-delta isozymes is evolutionarily conserved even in non-mammalian species, such as yeast, slime molds and plants.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1972267206 151 IRLAFKVFDKDGNGYITAQEFKHFMTTMGERFSEEEVDEIIREVDKDGDEQIDLDEFVN 209
Cdd:cd16202     2 LKDQFRKADKNGDGKLSFKECKKLLKKLNVKVDKDYAKKLFQEADTSGEDVLDEEEFVQ 60