ATPase-like domain of the ASKHA (Acetate and Sugar Kinases/Hsc70/Actin) superfamily; The ASKHA superfamily, also known as actin-like ATPase domain superfamily, includes acetate and sugar kinases, heat-shock cognate 70 (Hsp70) and actin family proteins. They either function as conformational hydrolases (e.g. Hsp70, actin) that perform simple ATP hydrolysis, or as metabolite kinases (e.g. glycerol kinase) that catalyze the transfer of a phosphoryl group from ATP to their cognate substrates. Both activities depend on the presence of specific metal cations. ASKHA superfamily members share a common core fold that includes an actin-like ATPase domain consisting of two subdomains (denoted I _ II) with highly similar ribonuclease (RNase) H-like folds. The fold of each subdomain is characterized by a central five strand beta-sheet and flanking alpha-helices. The two subdomains form an active site cleft in which ATP binds at the bottom. Another common feature of ASKHA superfamily members is the coupling of phosphoryl-group transfer to conformational rearrangement, leading to domain closure. Substrate binding triggers protein motion.

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                  ....*....|....*....|....*...
gi 1360798633   1 FAGDDAPRAVFPSIVGRPRHHGIMIGMG 28
Cdd:cd10224    16 FAGDDAPRAVFPSIVGRPRHQGVMVGMG 43

nucleotide-binding domain (NBD) of actin and similar proteins; Actin is a ubiquitous protein involved in the formation of filaments that are major components of the cytoskeleton. It is a highly dynamic structural protein network involved in processes such as cell contraction, cell motility, vesicle trafficking, intracellular organization, cytokinesis, endocytosis and apoptosis. Actin is a monomeric globular protein (G-actin) that reversibly polymerizes to form filaments (F-actin). Each actin protomer binds one molecule of ATP and either calcium or magnesium ions. At low salt concentrations, actin exists as a monomer, and as the salt concentration rises F-actin forms, with the consequent hydrolysis of ATP. F-actin assembly is in constant flux with G-actin association occurring at the barbed end (+) and its disassociation at the pointed end (-). Actin monomers that have been released from the pointed end can be reused, if the ADP is exchanged for ATP. F-actin filaments can assemble into higher order structures, for example branched F-actin, and stress fibers. Actin binding proteins regulate actin filament dynamics by a range of functions including actin severing, depolymerizing, capping, stabilizing and de novo actin polymerization. Actins interaction with myosin is the basis of muscular contraction and many aspects of cell motility. In vertebrates there are three main groups of actin isoforms, alpha, beta and gamma. The alpha actins found in muscle tissues are a major constituent of the contractile apparatus. The beta and gamma actins co-exist in most cell types as components of the cytoskeleton and as mediators of internal cell motility. In plants there are many isoforms which are probably involved in a variety of functions such as cytoplasmic streaming, cell shape determination, tip growth, graviperception, cell wall deposition, etc.

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                  ....*....|....*....|....*...
gi 1360798633   1 FAGDDAPRAVFPSIVGRPRHHGIMIGMG 28
Cdd:cd10224    16 FAGDDAPRAVFPSIVGRPRHQGVMVGMG 43

Actin;

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                  ....*....|....*....|....
gi 1360798633   1 FAGDDAPRAVFPSIVGRPRHHGIM 24
Cdd:pfam00022  17 FAGEDAPKAVIPSCVGKPRGTKVE 40

nucleotide-binding domain (NBD) of actin and similar proteins; Actin is a ubiquitous protein involved in the formation of filaments that are major components of the cytoskeleton. It is a highly dynamic structural protein network involved in processes such as cell contraction, cell motility, vesicle trafficking, intracellular organization, cytokinesis, endocytosis and apoptosis. Actin is a monomeric globular protein (G-actin) that reversibly polymerizes to form filaments (F-actin). Each actin protomer binds one molecule of ATP and either calcium or magnesium ions. At low salt concentrations, actin exists as a monomer, and as the salt concentration rises F-actin forms, with the consequent hydrolysis of ATP. F-actin assembly is in constant flux with G-actin association occurring at the barbed end (+) and its disassociation at the pointed end (-). Actin monomers that have been released from the pointed end can be reused, if the ADP is exchanged for ATP. F-actin filaments can assemble into higher order structures, for example branched F-actin, and stress fibers. Actin binding proteins regulate actin filament dynamics by a range of functions including actin severing, depolymerizing, capping, stabilizing and de novo actin polymerization. Actins interaction with myosin is the basis of muscular contraction and many aspects of cell motility. In vertebrates there are three main groups of actin isoforms, alpha, beta and gamma. The alpha actins found in muscle tissues are a major constituent of the contractile apparatus. The beta and gamma actins co-exist in most cell types as components of the cytoskeleton and as mediators of internal cell motility. In plants there are many isoforms which are probably involved in a variety of functions such as cytoplasmic streaming, cell shape determination, tip growth, graviperception, cell wall deposition, etc.

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                  ....*....|....*....|....*...
gi 1360798633   1 FAGDDAPRAVFPSIVGRPRHHGIMIGMG 28
Cdd:cd10224    16 FAGDDAPRAVFPSIVGRPRHQGVMVGMG 43

nucleotide-binding domain (NBD) of actin, actin-related proteins T1-T3 (Arp-T1-3), and similar proteins; The family includes actin and human actin-related proteins T1, T2, and T3. Actin is a ubiquitous protein involved in the formation of filaments that are major components of the cytoskeleton. It is a highly dynamic structural protein network involved in processes such as cell contraction, cell motility, vesicle trafficking, intracellular organization, cytokinesis, endocytosis and apoptosis. Arp-T1, encoded by ACTRT1/ARPT1 gene expressed in testis, negatively regulates the Hedgehog (SHH) signaling, binds to the promoter of the SHH signaling mediator, GLI1, and inhibits its expression. Arp-T2 (also called actin-related protein M2; encoded by ACTRT2/ARPM2 gene expressed in testis and various other cell types) and Arp-T3 (also called actin-related protein M1; encoded by ACTRT3/ARPM1 gene expressed in all tested human tissues) play general roles in the organization of the cytoskeleton like other cytoplasmic actin-related proteins.

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                  ....*....|....*....|....*...
gi 1360798633   1 FAGDDAPRAVFPSIVGRPRHHGIMIGMG 28
Cdd:cd13397    16 FAGEDLPRAVFPSVVGRPKYKAVMLGAG 43

nucleotide-binding domain (NBD) of actin-related protein 1 (Arp1) and similar proteins; Arp1, also called centractin, actin-like protein, alpha-centractin, actin-RPV, or centrosome-associated actin homolog, may be a component of a multi-subunit centrosomal complex involved in microtubule-based vesicle motility. In yeast, actin-related protein is essential for viability and is associated with the centrosome. In vertebrates, Arp1 is a core component of the dynactin complex which assists cytoplasmic dynein by increasing its processivity and by regulation of its cargo binding. The dynactin complex is required for the spindle translocation late in anaphase and is involved in a cell wall synthesis checkpoint. ARP1 forms the backbone filament of the dynactin rod structure and serves as the scaffold for the remaining subunits. It is required for proper orientation of the mitotic spindle. Arp1 is the only actin-related protein known to form actin-like filaments. Human Arp1/centractin is encoded by the ACTR1A gene.

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gi 1360798633   1 FAGDDAPRAVFPSIVGRPRHHGIMIG 26
Cdd:cd10216    17 FAGDDIPKVVFPSYVGRPKHVRVMAG 42

Actin; ACTIN subfamily of ACTIN/mreB/sugarkinase/Hsp70 superfamily

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gi 1360798633    1 FAGDDAPRAVFPSIVGRPRHHGIMIG 26
Cdd:smart00268  17 FAGEDFPQVVFPSIVGRPKDGKGMVG 42

nucleotide-binding domain (NBD) of actin-related protein2 (Arp2) and similar proteins; Arp2, also called actin-like protein 2, is the ATP-binding component of the Arp2/3 complex, a multiprotein complex that mediates actin polymerization upon stimulation by nucleation-promoting factor (NPF). The Arp2/3 complex is comprised of 7 proteins (Arp2, Arp3, and five conserved proteins, ARPC1-5). It generates cytoplasmic branched filaments networks, by promoting nucleation of actin filaments as 70 degrees branches on the side of older filaments. It is activated, by simultaneously binding to a pre-existing filament and a nucleation promoting factor plus an actin monomer. Daughter branches subsequently detach/debranch from the mother filament. Its Arp2 and Arp3 subunits must be loaded with ATP for it to initiate the assembly of branched actin filaments. ATP hydrolysis may be required for branch initiation or debranching. The Arp2/3 complex is also found in the nucleus where it plays a role in promoting de novo actin polymerization and in RNA polymerase II-dependent transcription. This may in part be through regulating nuclear actin polymerization in a way like its function in the cytoplasm. Human Arp2 is encoded by the ACTR2 gene.

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gi 1360798633   1 FAGDDAPRAVFPSIVGRP 18
Cdd:cd10220    16 FAGSNFPEHVFPSLVGRP 33

nucleotide-binding domain (NBD) of actin-related protein5 (Arp5) and similar proteins; Arp5, also called actin-like protein 5, may act as a core component of the chromatin remodeling INO80 complex which is involved in transcriptional regulation, DNA replication and probably DNA repair. It is involved in DNA double-strand break repair and UV-damage excision repair. Human Arp5 is encoded by the ACTR5 gene. Arabidopsis thaliana ARP5 (AtARp5) is a ubiquitously expressed nuclear protein involved in DNA repair and required for multicellular development of all organs. AtARp5 may be part of other chromatin remodeling machines in addition to INO80.

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gi 1360798633   1 FAGDDAPRAVFPSIVGRPRH 20
Cdd:cd10211    15 WAGDKEPRLVFRNLVAKPRD 34