InterPro domain: IPR001698

The F-actin capping protein binds in a calcium-independent manner to the fast growing ends of actin filaments (barbed end) and thereby restricts its growth. The F-actin capping protein is a heterodimer composed of two unrelated subunits: alpha and beta. Neither of the subunits shows sequence similarity to other filament-capping proteins [ 1 ].

This entry represents the beta subunit (CAPZB), which is a protein of about 280 amino acid residues whose sequence is well conserved in eukaryotic species [ 2 ]. In Drosophila mutations in the alpha and beta subunits cause actin accumulation and subsequent retinal degeneration [ 3 ]. In humans CAPZB is part of the WASH complex that controls the fission of endosomes [ 4 ].

1. Beta-actinin is equivalent to Cap Z protein. J. Biol. Chem. 265, 8712-5
2. Disruption of the actin cytoskeleton in yeast capping protein mutants. Nature 344, 352-4
3. Mutations in the Drosophila orthologs of the F-actin capping protein alpha- and beta-subunits cause actin accumulation and subsequent retinal degeneration. Genetics 171, 1757-65
4. The Arp2/3 activator WASH controls the fission of endosomes through a large multiprotein complex. Dev. Cell 17, 712-23