F-actin capping protein

In molecular biology, the F-actin capping protein is a protein complex which binds in a calcium-independent manner to the fast-growing ends of actin filaments (barbed end), thereby blocking the exchange of subunits at these ends. Unlike gelsolin and severin this protein does not sever actin filaments. 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] The alpha subunit is a protein of about 268 to 286 amino acid residues and the beta subunit is approximately 280 amino acids, their sequences are well conserved in eukaryotic species.^[2]

F-actin capping protein alpha subunit
solution nmr structure of s100b bound to the high-affinity target peptide trtk-12
Identifiers
Symbol	F-actin_cap_A
Pfam	PF01267
InterPro	IPR018315
PROSITE	PDOC00609
SCOP2	1izn / SCOPe / SUPFAM
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

F-actin capping protein, beta subunit
Identifiers
Symbol	F_actin_cap_B
Pfam	PF01115
InterPro	IPR001698
PROSITE	PDOC00203
SCOP2	1izn / SCOPe / SUPFAM
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The actin filament system, a prominent part of the cytoskeleton in eukaryotic cells, is both a static structure and a dynamic network that can undergo rearrangements: it is thought to be involved in processes such as cell movement and phagocytosis, as well as muscle contraction.^[1]