Cytoskeleton | Actin-Capping and Severing Proteins

Actin cytoskeleton drives many aspects of cell function, such as cytokinesis, regulation of cell adhesion, shape, motility and trafficking inside the cell. Actin is present in cells as monomeric G-actin, and filamentous actin (F-actin). Many cellular functions of actin are achieved by its dynamic assembly and disassembly at the ends of the filaments, which are regulated by many actin-binding proteins (ABPs). Actin-capping and -severing proteins are special classes of ABPs. Actin-capping proteins inhibit the filament growth and/or depolymerization at the filament ends. F-actin severing proteins enhance filament breakage and depolymerization by providing more free ends from which subunit dissociation can occur. Thus, actin filament dynamicity is regulated by the activity of capping and severing proteins.