Aktinbindende

Aktinbindende (actin-binding) proteins are a diverse set of proteins that interact with actin filaments (F-actin) and, in many cases, actin monomers (G-actin). They regulate the cytoskeleton by controlling polymerization and depolymerization, nucleation, crosslinking, capping, severing, anchoring, and network organization. Through these actions, they influence cell shape, adhesion, motility, division, and endocytosis.

Key families and examples include the Arp2/3 complex that nucleates branched networks; formins that promote linear filament elongation; profilin that binds G-actin and accelerates nucleotide exchange; cofilin that severs and depolymerizes filaments; tropomyosin that stabilizes filaments; CapZ that caps barbed ends; tropomodulin that caps pointed ends; and crosslinkers such as fimbrin, α-actinin, and filamin. Some actin-binding proteins also interact with membranes or signaling molecules to coordinate cytoskeletal changes with cellular activities.

Most aktinbindende proteins contain actin-binding domains (ABD) such as calponin-homology (CH) domains, and their activity is regulated by calcium, phosphorylation, pH, and interactions with other proteins. Their localization spans the cytoplasm and cellular cortex, and they operate within coordinated signaling networks to shape dynamic processes such as migration, cytokinesis, and endocytosis.

Dysfunction or mutations in actin-binding proteins are linked to diseases including cardiomyopathies, deafness, neurodegenerative disorders, and cancer cell invasion. Researchers study aktinbindende proteins using biochemical assays, fluorescence microscopy, and structural methods to understand how they control actin dynamics.