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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 320545551  22 EVEIKDLRTAFDLLDRNRDGRVTANELQFMLknlginvsDELIHDLIREASHSGNGLINEAEFLQWVGRIQAlrdeqhsh 101
Cdd:COG5126    1 DLQRRKLDRRFDLLDADGDGVLERDDFEALF--------RRLWATLFSEADTDGDGRISREEFVAGMESLFE-------- 64

                         90       100       110       120       130       140       150
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 320545551 102 edskdskpvdeaDDVTEDLIAAFRVFDRDGNGFITRDELQTAMEMIGepLNEQQLEQLLVIADLDQDGRINYEEFTRLL 180
Cdd:COG5126   65 ------------ATVEPFARAAFDLLDTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAV 129

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 320545551  118 EDLIAAFRVFDRDGNGFITRDELQTAMEMI--GEPLNEQQLEQLLVIADLDQDGRINYEEFTRLLL 181
Cdd:pfam13499   2 EKLKEAFKLLDSDGDGYLDVEELKKLLRKLeeGEPLSDEEVEELFKEFDLDKDGRISFEEFLELYS 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 320545551   119 DLIAAFRVFDRDGNGFITRDELQTAMEMI 147
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

centrin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 320545551  10 RATKSVKKKPFTEVEIKDLRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLIREASHSGNGLINEAEFLqwvg 89
Cdd:PTZ00183   1 MRKRRSERPGLTEDQKKEIREAFDLFDTDGSGTIDPKELKVAMRSLGFEPKKEEIKQMIADVDKDGSGKIDFEEFL---- 76

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 320545551  90 riqalrDEQHSHEDSKDSKpvdeaddvtEDLIAAFRVFDRDGNGFITRDELQTAMEMIGEPLNEQQLEQLLVIADLDQDG 169
Cdd:PTZ00183  77 ------DIMTKKLGERDPR---------EEILKAFRLFDDDKTGKISLKNLKRVAKELGETITDEELQEMIDEADRNGDG 141

                        170
                 ....*....|.
gi 320545551 170 RINYEEFTRLL 180
Cdd:PTZ00183 142 EISEEEFYRIM 152

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 320545551 119 DLIAAFRVFDRDGNGFITRDELQTAMEMIGEPLNEQQLEQLLVIADLDQDGRINYEEFTRLL 180
Cdd:cd00051    1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELM 62

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 320545551  118 EDLIAAFRVFDRDGNGFITRDELQTAMEMI--GEPLNEQQLEQLLVIADLDQDGRINYEEFTRLLL 181
Cdd:pfam13499   2 EKLKEAFKLLDSDGDGYLDVEELKKLLRKLeeGEPLSDEEVEELFKEFDLDKDGRISFEEFLELYS 67

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 320545551  27 DLRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLIREASHSGNGLINEAEFLQWV 88
Cdd:cd00051    1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELM 62

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 320545551  18 KPFTEVEIKDLRTAFDLLDRNRDGRVTANELQFMLKNLGinVSDELIHDLIREASHSGNGLINEAEFLQWV 88
Cdd:COG5126   61 SLFEATVEPFARAAFDLLDTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAV 129

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 320545551  28 LRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLIREASHSGNGLINEAEFLQ 86
Cdd:cd16202    2 LKDQFRKADKNGDGKLSFKECKKLLKKLNVKVDKDYAKKLFQEADTSGEDVLDEEEFVQ 60

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 320545551 118 EDLIAAFRVFDRDGNGFITRDELQTAMEMI-----GEPLNEQQLEQLLVIADLDQDGRINYEEFTRLL 180
Cdd:cd16252   37 EAIRKAFQMLDKDKSGFIEWNEIKYILSTVpssmpVAPLSDEEAEAMIQAADTDGDGRIDFQEFSDMV 104

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 320545551  25 IKDLRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLIREASHSGNGLINEAEFLQWVGRIQALRDeqhsheds 104
Cdd:cd16183   66 ITDWQNCFRSFDRDNSGNIDKNELKQALTSFGYRLSDQFYDILVRKFDRQGRGTIAFDDFIQCCVVLQTLTD-------- 137

                         90       100       110
                 ....*....|....*....|....*....|..
gi 320545551 105 kdskpvdeaddvtedliaAFRVFDRDGNGFIT 136
Cdd:cd16183  138 ------------------SFRRYDTDQDGWIQ 151

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 320545551  24 EIKDLRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLIREASHSGNGLINEAEFLQWVGRIQALRDeqhshed 103
Cdd:cd16180   65 YIQDWRRLFRRFDRDRSGSIDFNELQNALSSFGYRLSPQFVQLLVRKFDRRRRGSISFDDFVEACVTLKRLTD------- 137

                         90       100       110
                 ....*....|....*....|....*....|...
gi 320545551 104 skdskpvdeaddvtedliaAFRVFDRDGNGFIT 136
Cdd:cd16180  138 -------------------AFRKYDTNRTGYAT 151

Penta-EF hand, calcium binding motifs, found in calpain-13 (CAPN13), calpain-14 (CAPN14), and similar proteins; CAPN13, also termed calcium-activated neutral proteinase 13 (CANP 13), a 63.6 kDa calpain large subunit that exhibits a restricted tissue distribution with low levels of expression detected only in human testis and lung. In calpain family, CAPN13 is most closely related to calpain-14 (CAPN14). CAPN14, also termed calcium-activated neutral proteinase 14 (CANP 14), is a 76.7 kDa calpain large subunit that is most highly expressed in the oesophagus. Its expression and calpain activity can be induced by IL-13. Both CAPN13 and CAPN14 contain a calpain cysteine protease (CysPc) domain, a C2-domain-like (C2L) domain, and a C-terminal Ca2+-binding penta-EF-hand (PEF) domain.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 320545551 124 FRVFDRDGNGFITRDELQTAMEMIGEPLNEQQLeQLLVIADLDQDGRINYEEFTRLLL 181
Cdd:cd16195   79 FQKADVSKSGFLSLSELRNAIQAAGIRVSDDLL-NLMALRYGDSSGRISFESFICLML 135

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 320545551 118 EDLIAAFRVFDRDGNGFITRDELQTAMEMI---GEPLNEQQLEQLLVIADLDQDGRINYEEFTRLL 180
Cdd:cd16254   34 DDVKKVFHILDKDKSGFIEEDELKFVLKGFspdGRDLSDKETKALLAAGDKDGDGKIGIDEFATLV 99

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
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 320545551  28 LRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLIREASHSGNGLINEAEF 84
Cdd:cd15898    2 LRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEF 58

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 320545551  32 FDLLDRNRDGRVTANELQFMLKNLGIN-VSDELIHDLIREASHSGNGLINEAEFLQWVGRIQalrdeqhshedskdskpv 110
Cdd:cd16183    6 FQRVDKDRSGQISATELQQALSNGTWTpFNPETVRLMIGMFDRDNSGTINFQEFAALWKYIT------------------ 67

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 320545551 111 deaddvteDLIAAFRVFDRDGNGFITRDELQTAMEMIGEPLNEQQLEQLLVIADLDQDGRINYEEF 176
Cdd:cd16183   68 --------DWQNCFRSFDRDNSGNIDKNELKQALTSFGYRLSDQFYDILVRKFDRQGRGTIAFDDF 125

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        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 320545551  25 IKDLRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLIREASHSGNGLINEAEFLQWVGRIQALRDE 97
Cdd:cd16184   66 IQQWKQVFQQFDRDRSGSIDENELHQALSQMGYRLSPQFVQFLVSKYDPRARRSLTLDQFIQVCVQLQSLTDA 138

Penta-EF hand, calcium binding motifs, found in PEF calpain family; The PEF calpain family belongs to the second group of penta-EF hand (PEF) proteins. It includes classical (also called conventional or typical) calpain (referring to a calcium-dependent papain-like enzymes, EC 3.4.22.17) large catalytic subunits (CAPN1, 2, 3, 8, 9, 11, 12, 13, 14) and two calpain small subunits (CAPNS1 and CAPNS2), which are largely confined to animals (metazoans). These PEF-containing are nonlysosomal intracellular calcium-activated intracellular cysteine proteases that play important roles in the degradation or functional modulation in a variety of substrates in response to calcium signalling. The classical mu- and m-calpains are heterodimers consisting of homologous but a distinct (large) L-subunit/chain (CAPN1 or CAPN2) and a common (small) S-subunit/chain (CAPNS1 or CAPNS2). These L-subunits (CAPN1 and CAPN2) and S-subunit CAPNS1 are ubiquitously found in all tissues. Other calpains likely consist of an isolated L-subunit/chain alone. Many of them, such as CAPNS2, CAPN3 (in skeletal muscle, or lens), CAPN8 (in stomach), CAPN9 (in digestive tracts), CAPN11 (in testis), CAPN12 (in follicles), are tissue-specific and have specific functions in distinct organs. The L-subunits of similar structure (called CALPA and B) also have been found in Drosophila melanogaster. The S-subunit seems to have a chaperone-like function for proper folding of the L-subunit. The catalytic L-subunits contain a short N-terminal anchor helix, followed by a calpain cysteine protease (CysPc) domain, a C2-domain-like (C2L) domain, and a C-terminal Ca2+-binding penta-EF-hand (PEF) domain. The S-subunits only have the PEF domain following an N-terminal Gly-rich hydrophobic domain. The calpains undergo a rearrangement of the protein backbone upon Ca2+-binding.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 320545551  38 NRDGRVTANELQ---------FMLKNLGINVsdELIHDLIREASHSGNGLINEAEFLQWVGRIQALRdeqhshedskdsk 108
Cdd:cd16182   11 GEDEEIDAVELQkllnasllkDMPKFDGFSL--ETCRSLIALMDTNGSGRLDLEEFKTLWSDLKKWQ------------- 75

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 320545551 109 pvdeaddvtedliAAFRVFDRDGNGFITRDELQTAMEMIGEPLNEQQLeQLLVIADLDQDGRINYEEF 176
Cdd:cd16182   76 -------------AIFKKFDTDRSGTLSSYELRKALESAGFHLSNKVL-QALVLRYADSTGRITFEDF 129

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

                          10        20
                  ....*....|....*....|....*....
gi 320545551  119 DLIAAFRVFDRDGNGFITRDELQTAMEMI 147
Cdd:pfam00036   1 ELKEIFRLFDKDGDGKIDFEEFKELLKKL 29

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 320545551   119 DLIAAFRVFDRDGNGFITRDELQTAMEMI 147
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLKAL 29

EF-hand, calcium binding motif, found in Drosophila melanogaster calbindin-32 (CBN) and similar proteins; CBN, the product of the cbn gene, is a Drosophila homolog to vertebrate neuronal six EF-hand calcium binding proteins. It is expressed through most of ontogenesis with a selective distribution in the nervous system and in a few small adult thoracic muscles. Its precise biological role remains unclear. CBN contains six EF-hand motifs, but some of them may not bind calcium ions due to the lack of key residues.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 320545551 118 EDLIAAFRVFDRDGNGFITRDE----LQTAMEMIGEPLNEQQLEQ----LLVIADLDQDGRINYEEFTRLLL 181
Cdd:cd16179  188 EDIDRVFALYDRDNNGTIENEEltgfLKDLLELVQEDYDEQDLEEfkeiILRGWDFNNDGKISRKELTMLLL 259

EF-hand, calcium binding motif, found in reticulocalbin-3 (RCN-3); RCN-3, also termed EF-hand calcium-binding protein RLP49, 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 His-Asp-Glu-Leu (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 320545551  28 LRTAFDLLDRNRDGRVTANELQfmLKNLGINVSDELIHDL----------------IREASHSGNGLINEAEFLQWvgri 91
Cdd:cd16230   75 VSAAWQTYDTDRDGRVGWEELR--NATYGHYEPGEEFHDVedaetykkmlarderrFRVADQDGDSMATREELTAF---- 148

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 320545551  92 qaLRDEQHSHedskdSKPVDEADDVtEDLiaafrvfDRDGNGFITRDE----LQTAMEMIGEPLNEQQLEQLLVIA-DLD 166
Cdd:cd16230  149 --LHPEEFPH-----MRDIVVAETL-EDL-------DKNKDGYVQVEEyiadLYSGEPGEEEPAWVQTERQQFRQFrDLN 213

                        170
                 ....*....|....*
gi 320545551 167 QDGRINYEEFTRLLL 181
Cdd:cd16230  214 KDGRLDGSEVGHWVL 228

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.

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gi 320545551 118 EDLIAAFRVFDRDGNGFITRDELQ----TAMEMIGEPLNEQQLEQ----LLVIADLDQDGRINYEEFTRLL 180
Cdd:cd15902   90 VEFMKIWRKYDTDGSGFIEAKELKgflkDLLLKNKKHVSPPKLDEytklILKEFDANKDGKLELDEMAKLL 160

EF-hand, calcium binding motif, found in parvalbumins; Parvalbumins are small, acidic, cytosolic EF-hand-containing Ca2+-buffer and Ca2+ transporter/shuttle proteins belonging to EF-hand superfamily. They are expressed by vertebrates in fast-twitch muscle cells, specific neurons of the central and peripheral nervous system, sensory cells of the mammalian auditory organ (Corti's cell), and some other cells, and 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+. Thus, they may play an additional role in Mg2+ handling. Moreover, parvalbumins represent one of the major animal allergens. In metal-bound states, parvalbumins possess a rigid and stable tertiary structure and display strong allergenicity. In contrast, the metal-free parvalbumins are intrinsically disordered, and the loss of metal ions results in a conformational change that decreases their IgE binding capacity. Furthermore, parvalbumins have been widely used as a neuronal marker for a variety of functional brain systems. They also function as a Ca2+ shuttle transporting Ca2+ from troponin-C (TnC) to the sarcoplasmic reticulum (SR) Ca2+ pump during muscle relaxation. Thus they may facilitate myocardial relaxation and play important roles in cardiac diastolic dysfunction. Parvalbumins consists of alpha- and beta- sublineages, which can be distinguished on the basis of isoelectric point (pI > 5 for alpha; pI

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gi 320545551 119 DLIAAFRVFDRDGNGFITRDELQTAMEMI---GEPLNEQQLEQLLVIADLDQDGRINYEEFTRL 179
Cdd:cd16253   35 DIKKVFNILDQDKSGFIEEEELKLFLKNFsdgARVLSDKETKNFLAAGDSDGDGKIGVDEFKSM 98

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.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 320545551  39 RDGRVTANELQFMLKNLGINVSDE---------LIHDLIREasHSGNGLINEAEFLqWvgriQALRDEQHShedskdskp 109
Cdd:cd16181   12 QDGQIDADELQRCLTQSGISGNYQpfsletcrlMIAMLDRD--HSGKMGFNEFKEL-W----AALNQWKTT--------- 75

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gi 320545551 110 vdeaddvtedliaaFRVFDRDGNGFITRDELQTAMEMIGEPLNEQQLEqlLVIADLDQDGRINYEEF 176
Cdd:cd16181   76 --------------FMQYDRDRSGTVEPQELQQAIRSFGYNLSPQALN--VIVKRYSKNGRITFDDF 126

N-terminal domain of Myosin essential light chain ELC; ELC is part of the apicomplexan membrane-associated protein complex called the glideosome, which is essential for parasite motility. The glideosome is composed of six proteins: myosin A (MyoA), essential light chain ELC, myosin light chain MLC1 (also called MTIP), and the glideosome-associated proteins GAP40, GAP45, and GAP50. MyoA is a Class XIV myosin implicated in gliding motility, as well as host cell and tissue invasion by parasites. ELC binds to the MyoA neck region adjacent to the MLC1-binding site, and both myosin light chains co-located to the glideosome. Although ELCs bind to a conserved MyoA sequence, P. falciparum ELC adopts a distinct structure in the free and MyoA-bound state. Therefore ELCs enhance MyoA performance by inducing alpha helical structure formation in MyoA and thus stiffening its lever arm. It has been shown that disruption of MyoA, MLC1, or ELC have dramatic effects on parasite motility but do not affect parasite shape or replication. The ELC N-terminal domain is part of the EF-hand calcium binding motif superfamily. Calcium binding has no effect on the structure of ELCs.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 320545551  28 LRTAFDLLDRNRDGRVTANELQFMLKNLGINVSDELIHDLireashsgNGLINEAEFLQWV 88
Cdd:cd22949    5 FREAFILFDRDGDGELTMYEAVLAMRSCGIPLTNDEKDAL--------PASMNWDQFENWA 57

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.

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gi 320545551 122 AAFRVFDRDGNGFITRDELQTAMEMIGEPLNEQQLEQlLVIADLDQDGRINYEEF 176
Cdd:cd16196   75 RVFKLFDTDGSGSFSSFELRNALNSAGFRLSNATLNA-LVLRYSNKDGRISFDDF 128

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.

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                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 320545551 124 FRVFDRDGNGFITRDELQTAMEMI-GEPLNEQQLEQLLVIADLDQDGRINYEEFTRL 179
Cdd:cd16184    6 FQAVDRDRSGKISAKELQQALVNGnWSHFNDETCRLMIGMFDKDKSGTIDIYEFQAL 62