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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  24 EEQKQEIKDAFELFDTDKDEAIDYHELKVAMRALgfdvkkadVLKILKDYDREATGKITFEDFNEVVTDWiLERDPHEEI 103
Cdd:COG5126   1 DLQRRKLDRRFDLLDADGDGVLERDDFEALFRRL--------WATLFSEADTDGDGRISREEFVAGMESL-FEATVEPFA 71

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 46397403 104 LKAFKLFDDDDSGKISLRNLRRVARELGenMSDEELRAMIEEFDKDGDGEINQEEFIAIMTG 165
Cdd:COG5126  72 RAAFDLLDTDGDGKISADEFRRLLTALG--VSEEEADELFARLDTDGDGKISFEEFVAAVRD 131

EF-hand domain pair;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 46397403   101 EEILKAFKLFDDDDSGKISLRNLRRVAR--ELGENMSDEELRAMIEEFDKDGDGEINQEEFIAIMT 164
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 46397403    138 ELRAMIEEFDKDGDGEINQEEFIAIMT 164
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLK 27

calmodulin; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403   21 ELSEEQKQEIKDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREATGKITFEDFNEVVTDWILERDPH 100
Cdd:PTZ00184   4 QLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADGNGTIDFPEFLTLMARKMKDTDSE 83

                         90       100       110       120       130       140
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 46397403  101 EEILKAFKLFDDDDSGKISLRNLRRVARELGENMSDEELRAMIEEFDKDGDGEINQEEFIAIMT 164
Cdd:PTZ00184  84 EEIKEAFKVFDRDGNGFISAAELRHVMTNLGEKLTDEEVDEMIREADVDGDGQINYEEFVKMMM 147

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 46397403 102 EILKAFKLFDDDDSGKISLRNLRRVARELGENMSDEELRAMIEEFDKDGDGEINQEEFIAIMT 164
Cdd:cd00051   1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 63

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 46397403  29 EIKDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREATGKITFEDFNEVvtdwilerdpHEEILK--- 105
Cdd:cd16185   1 ELRQWFRAVDRDRSGSIDVNELQKALAGGGLLFSLATAEKLIRMFDRDGNGTIDFEEFAAL----------HQFLSNmqn 70

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 46397403 106 AFKLFDDDDSGKISLRNLRRVARELGENMSDEELRAMIEEFDKDGDGEINQEEFIAI 162
Cdd:cd16185  71 GFEQRDTSRSGRLDANEVHEALAASGFQLDPPAFQALFRKFDPDRGGSLGFDDYIEL 127

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 46397403  29 EIKDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREATGKITFEDFNEVVT 91
Cdd:cd00051   1 ELREAFRLFDKDGDGTISADELKAALKSLGEGLSEEEIDEMIREVDKDGDGKIDFEEFLELMA 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 46397403  30 IKDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREATGKITFEDFNEVVTDwILERDpheEILKAFKL 109
Cdd:cd15898   2 LRRQWIKADKDGDGKLSLKEIKKLLKRLNIRVSEKELKKLFKEVDTNGDGTLTFDEFEELYKS-LTERP---ELEPIFKK 77

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 46397403 110 FDDDDSGKISLRNLRRVAR-ELGENMSDEELRAMIEEFDKDGDGE-INQEEFIAIMTGD 166
Cdd:cd15898  78 YAGTNRDYMTLEEFIRFLReEQGENVSEEECEELIEKYEPERENRqLSFEGFTNFLLSP 136

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 46397403  33 AFELFDTDKDEAIDYHELKVAMRAL--------------GFDVKKADVLKILKDY--DREATGKITFEDFNEVVTDWILE 96
Cdd:cd15900   5 AFKMFDLDGDGELDKEEFNKVQSIIrsqtsvgqrhrdhtNGESTKLGMNSTLARYffGKDGKQKLSIEKFLEFQENLQEE 84

                        90       100       110       120       130       140
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 46397403  97 RDPHEEILKAFKLFDDDdsgkISLRNLRRVAREL-GENMSDEELRAMIEEFDKDGDGEINQEEFIAIM 163
Cdd:cd15900  85 IDDVDTALTFYHLAGAS----IDRKTFKRAAKVVaGVELSDHVVDVVFTIFDEDGDGILSHKEFISVM 148

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 46397403  73 YDREATGKITFEDFNEV---VTDWilerdpheeiLKAFKLFDDDDSGKISLRNLRRVARELGENMSDEELRAMIEEFDKD 149
Cdd:cd16183  46 FDRDNSGTINFQEFAALwkyITDW----------QNCFRSFDRDNSGNIDKNELKQALTSFGYRLSDQFYDILVRKFDRQ 115

                        90
                ....*....|.
gi 46397403 150 GDGEINQEEFI 160
Cdd:cd16183 116 GRGTIAFDDFI 126

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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  41 KDEAIDYHELK-----VAMRALGFDVKKADV---LKILKDYDReaTGKITFEDFNEVVTD---WilerdpheeiLKAFKL 109
Cdd:cd16196  12 EDMEIDAYELQdilntAFKKDFPFDGFSLDAcrsMVAMMDVDR--SGKLGFEEFKKLWEDlrsW----------KRVFKL 79

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*
gi 46397403 110 FDDDDSGKISLRNLRRVARELGENMSDEELRAMIEEFdKDGDGEINQEEFIAIMT 164
Cdd:cd16196  80 FDTDGSGSFSSFELRNALNSAGFRLSNATLNALVLRY-SNKDGRISFDDFIMCAV 133

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 46397403  28 QEIKDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREATGKITFEDF 86
Cdd:cd16184  67 QQWKQVFQQFDRDRSGSIDENELHQALSQMGYRLSPQFVQFLVSKYDPRARRSLTLDQF 125

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 46397403  95 LERDPHEEILKAFKLFDDDDSG-------KISLRNLRRVARELgenmSDEELRAMIEEFDKDGDGEINQEEFIAI 162
Cdd:cd16255  28 LSKKSADDVKKVFEIIDQDKSGfieeeelKLFLQNFSSGAREL----TDAETKAFLKAGDSDGDGKIGVEEFQAL 98

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 46397403    138 ELRAMIEEFDKDGDGEINQEEFIAIMT 164
Cdd:smart00054   1 ELKEAFRLFDKDGDGKIDFEEFKDLLK 27

EF-hand, calcium binding motif, found in parvalbumin-like EF-hand family; The family includes alpha- and beta-parvalbumins, and a group of uncharacterized calglandulin-like proteins. 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

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 46397403 101 EEILKAFKLFDDDDSGKISLRNLRRVAREL---GENMSDEELRAMIEEFDKDGDGEINQEEF 159
Cdd:cd16251  34 DQIKKVFQILDKDKSGFIEEEELKYILKGFsiaGRDLTDEETKALLAAGDTDGDGKIGVEEF 95

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
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 46397403 102 EILKAFKLFDDDDSGKISLRNLRR---VARelGENMSDEELRAMIEEFDKDGDGEINQEEF 159
Cdd:cd16184   1 EVQQWFQAVDRDRSGKISAKELQQalvNGN--WSHFNDETCRLMIGMFDKDKSGTIDIYEF 59

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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  31 KDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREaTGKITFEDFNEVVTdwILERdpheeILKAFKLF 110
Cdd:cd15897  73 QEIFRTYDTDGSGTIDSNELRQALSGAGYRLSEQTYDIIIRRYDRG-RGNIDFDDFIQCCV--RLQR-----LTDAFRRY 144

                        90
                ....*....|
gi 46397403 111 DDDDSGKISL 120
Cdd:cd15897 145 DKDQDGQIQV 154

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 46397403   138 ELRAMIEEFDKDGDGEINQEEFIAIMT 164
Cdd:pfam00036   1 ELKEIFRLFDKDGDGKIDFEEFKELLK 27

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

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  31 KDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDReaTGKITFEDFN------EVVTDWILERDPHEEIL 104
Cdd:cd16186  73 KQNFMTVDQDRSGTVEPHELRQAIGAMGYRLSPQTLTTIVKRYSK--NGRIYFDDYVaccvklRALTDFFRRRDHMQQGS 150

                ....*...
gi 46397403 105 KAFkLFDD 112
Cdd:cd16186 151 VNF-IYDD 157

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

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  74 DREATGKITFEDFNE---VVTDWilerdpheeiLKAFKLFDDDDSGKISLRNLRRVARELGENMSDEELRAMIEEFDKDG 150
Cdd:cd16186  50 DRDHTGKMGFNEFKElwaALNAW----------KQNFMTVDQDRSGTVEPHELRQAIGAMGYRLSPQTLTTIVKRYSKNG 119

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.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  77 ATGKITFEDFNEVVTdwiLERDPHEEILKAFKLFDDDDSGKISLRNLRRVAREL---GENMSDEELRAMIEEFDKDGDGE 153
Cdd:cd16254  13 AADSFDYKKFFEMVG---LKKKSADDVKKVFHILDKDKSGFIEEDELKFVLKGFspdGRDLSDKETKALLAAGDKDGDGK 89

                        90
                ....*....|
gi 46397403 154 INQEEFIAIM 163
Cdd:cd16254  90 IGIDEFATLV 99

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+.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 46397403 102 EILKAFKLFDDDDSGKISlrnlrrvARELGENMS--------DEELRAMIEEFDKDGDGEINQEEFIA 161
Cdd:cd16180   1 ELRRIFQAVDRDRSGRIS-------AKELQRALSngdwtpfsIETVRLMINMFDRDRSGTINFDEFVG 61

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 46397403  32 DAFELFDTDKDEAIDYHELKVAMRAL-----GFDVKKADVLK----ILKDYDREATGKITFEDFNEVVTDWI-----LER 97
Cdd:cd15902   3 EVWMHFDADGNGYIEGKELDSFLRELlkalnGKDKTDDEVAEkkkeFMEKYDENEDGKIEIRELANILPTEEnflllFRR 82

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 46397403  98 DPHE----EILKAFKLFDDDDSGKISLRNLRRVAREL--------GENMSDEELRAMIEEFDKDGDGEINQEEF 159
Cdd:cd15902  83 EQPLissvEFMKIWRKYDTDGSGFIEAKELKGFLKDLllknkkhvSPPKLDEYTKLILKEFDANKDGKLELDEM 156

EF-hand, calcium binding motif, found in reticulocalbin-2 (RCN2); RCN2, also termed calcium-binding protein ERC-55, or E6-binding protein (E6BP), or TCBP-49, is an endoplasmic reticulum resident low-affinity Ca2+-binding protein that has been implicated in immunity, redox homeostasis, cell cycle regulation and coagulation. It is associated with tumorigenesis, in particular with transformation of cells of the cervix induced by human papillomavirus (HPV), through binding to human papillomavirus (HPV) E6 oncogenic protein. It specifically interacts with vitamin D receptor among nuclear receptors. RCN2 contains an N-terminal signal sequence followed by six copies of the EF-hand Ca2+-binding motif, and a C-terminal His-Asp-Glu-Leu (HDEL) tetrapeptide that is required for retention of RCN2 in the endoplasmic reticulum (ER).

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  23 SEEQKQEIKDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREATGKITFEDFNEVVTDWILE------ 96
Cdd:cd16224  31 PEEQQKRLKSIIKKIDTDSDGFLTEEELSSWIQQSFRHYALEDAKQQFPEYDKDGDGAVTWDEYNMQMYDRVIDydedtv 110

                        90       100       110       120       130       140       150
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 46397403  97 -RDPHEEI-----LKAFKLFDDDDSGKISLRNLRRVAR----ELGENMSDEELRAMIEEFDKDGDGEINQEEFI 160
Cdd:cd16224 111 lDDEEEESfrqlhLKDKKRFDKANTDGGPGLNLTEFIAfehpEEVDYMTEFVIQEALEEHDKDGDGFISLEEFL 184

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.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  24 EEQKQEIKDAFELFDTDKDEAIDYHELKVAMRALGFDVKKADVLKILKDYDREATGKITFEDFNEVV----TDWILERDP 99
Cdd:cd16226  31 EESKERLGIIVDKIDKNGDGFVTEEELKDWIKYVQKKYIREDVDRQWKEYDPNKDGKLSWEEYKKATygflDDEEEDDDL 110

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 46397403 100 HEEILKA-------FKLFDDDDSGKISLRNLRR-VARELGENMSDEELRAMIEEFDKDGDGEINQEEFIAIM 163
Cdd:cd16226 111 HESYKKMirrderrWKAADQDGDGKLTKEEFTAfLHPEEFPHMRDIVVQETLEDIDKNKDGFISLEEYIGDM 182

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.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 46397403  73 YDREATGKITFEDFNEVVTD---WilerdpheeiLKAFKLFDDDDSGKISLRNLRRVARELGENMSDEELRAMIEEFdKD 149
Cdd:cd16182  51 MDTNGSGRLDLEEFKTLWSDlkkW----------QAIFKKFDTDRSGTLSSYELRKALESAGFHLSNKVLQALVLRY-AD 119

                        90
                ....*....|.
gi 46397403 150 GDGEINQEEFI 160
Cdd:cd16182 120 STGRITFEDFV 130

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.

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gi 46397403  65 DVLKILKDYDREATGKITFEDFNEVVTDwILERDPHEEILKAFKLFDDDDSGKISL 120
Cdd:cd00051   1 ELREAFRLFDKDGDGTISADELKAALKS-LGEGLSEEEIDEMIREVDKDGDGKIDF 55