Wiskott-Aldrich Syndrome Homology (WASP) region 2 (WH2 motif), and similar proteins; This family contains the Wiskott-Aldrich syndrome protein (WASP)-homology domain 2 (WH2) as well as thymosin-beta (Tbeta; also called beta-thymosin or betaT) domains that are small, widespread intrinsically disordered actin-binding peptides displaying significant sequence variability and different regulations of actin self-assembly in motile and morphogenetic processes. These WH2/betaT peptides are identified by a central consensus actin-binding motif LKKT/V flanked by variable N-terminal and C-terminal extensions; the betaT shares a more extended and conserved C-terminal half than WH2. These single or repeated domains are found in actin-binding proteins (ABPs) such as the hematopoietic-specific protein WASP, its ubiquitously expressed ortholog neural-WASP (N-WASP), WASP-interacting protein (WAS/WASL-interacting protein family members 1 and 2), and WASP-family verprolin homologous protein (WAVE/SCAR) isoforms: WAVE1, WAVE2, and WAVE3. Also included are the WH2 domains found in inverted formin FH2 domain-containing protein (INF2), Cordon bleu (Cobl) protein, vasodilator-stimulated phosphoprotein (VASP) homology protein and actobindin (found in amoebae). These ABPs are commonly multidomain proteins that contain signaling domains and structurally conserved actin-binding motifs, the most important being the WH2 domain motif through which they bind actin in order to direct the location, rate, and timing for actin assembly in the cell into different structures, such as filopodia, lamellipodia, stress fibers, and focal adhesions. The WH2 domain motif is one of the most abundant actin-binding motifs in Wiskott-Aldrich syndrome proteins (WASPs) where they activate Arp2/3-dependent actin nucleation and branching in response to signals mediated by Rho-family GTPases. The thymosin beta (Tbeta) domains in metazoans act in cells as major actin-sequestering peptides; their complex with monomeric ATP-actin (G-ATP-actin) cannot polymerize at either filament (F-actin) end.

                         10        20
                 ....*....|....*....|....*....
gi 972131849  39 AGRGALLSDITKGKALKKAVTNDRSAPIV 67
Cdd:cd22076    3 AGRNALLSDINKGKKLKKTVTNDRSAPIL 31

Wiskott Aldrich syndrome homology region 2 (WH2 motif) in WAS/WASL-interacting protein family member 1; This family contains the Wiskott-Aldrich syndrome protein (WASP)-homology domain 2 (WH2) in WAS/WASL-interacting protein family (WIPF, also known as WASP-interacting protein or WIP) member 1 (WIPF1). WIPF1 is a ubiquitously expressed proline-rich multidomain protein and is a binding partner and chaperone of WASP. It stabilizes actin filaments and regulates actin organization and polymerization which are associated with cell migration and invasion. Mutations in the WIPF1 binding site of WASP or in WIPF1 itself cause Wiskott-Aldrich syndrome (WAS), a rare X-linked recessive disease characterized by eczema, thrombocytopenia, immune deficiency, and bloody diarrhea. Aberrant expression of WIPF1 contributes to the invasion and metastasis of several malignancies such breast cancer, glioma and colorectal cancer; it has been identified as an oncoprotein in human pancreatic ductal adenocarcinoma (PDAC) and is associated with poor survival.

                         10        20
                 ....*....|....*....|....*....
gi 972131849  39 AGRGALLSDITKGKALKKAVTNDRSAPIV 67
Cdd:cd22076    3 AGRNALLSDINKGKKLKKTVTNDRSAPIL 31

Wiskott Aldrich syndrome homology region 2 (WH2 motif) in WAS/WASL-interacting protein family member 1; This family contains the Wiskott-Aldrich syndrome protein (WASP)-homology domain 2 (WH2) in WAS/WASL-interacting protein family (WIPF, also known as WASP-interacting protein or WIP) member 1 (WIPF1). WIPF1 is a ubiquitously expressed proline-rich multidomain protein and is a binding partner and chaperone of WASP. It stabilizes actin filaments and regulates actin organization and polymerization which are associated with cell migration and invasion. Mutations in the WIPF1 binding site of WASP or in WIPF1 itself cause Wiskott-Aldrich syndrome (WAS), a rare X-linked recessive disease characterized by eczema, thrombocytopenia, immune deficiency, and bloody diarrhea. Aberrant expression of WIPF1 contributes to the invasion and metastasis of several malignancies such breast cancer, glioma and colorectal cancer; it has been identified as an oncoprotein in human pancreatic ductal adenocarcinoma (PDAC) and is associated with poor survival.

                         10        20
                 ....*....|....*....|....*....
gi 972131849  39 AGRGALLSDITKGKALKKAVTNDRSAPIV 67
Cdd:cd22076    3 AGRNALLSDINKGKKLKKTVTNDRSAPIL 31

WH2 motif; The WH2 motif (for Wiskott Aldrich syndrome homology region 2) has been shown in WASP and Scar1 (mammalian homolog) to be the region that interacts with actin.

                          10        20
                  ....*....|....*....|....*..
gi 972131849   38 GAGRGALLSDITKGKALKKA-VTNDRS 63
Cdd:pfam02205   2 GGGRGALLADIRAGKKLKKVeETNDRS 28

Wiskott Aldrich syndrome homology region 2 (WH2 motif) found in Actobindin and similar proteins; This family contains the Wiskott-Aldrich syndrome protein (WASP)-homology domain 2 (WH2) found in actobindin, an actin-binding protein from amoeba. Actobindin is able to bind two actin monomers at high concentrations of G-actin. It inhibits actin polymerization by sequestering G-actin and stabilizing actin dimers, thus making it a more potent inhibitor of the early phase of actin polymerization than of F-actin elongation.

                         10        20
                 ....*....|....*....|....*
gi 972131849  41 RGALLSDITKGKALKKAVTNDRSAP 65
Cdd:cd22063    5 RNSLLSEVEKGKELKHAETNDRSAP 29