actininteracting

Actin-interacting refers to proteins and molecules that bind to actin filaments or actin monomers to regulate the assembly, organization, and dynamics of the actin cytoskeleton. Actin-interacting proteins (ABPs) include nucleators, crosslinkers, and motors that control polymerization, filament branching, turnover, and contractility.

Nucleators such as the Arp2/3 complex and formins initiate filament formation. Elongation factors like profilin promote addition of actin monomers, while thymosin beta-4 sequesters actin monomers. Capping proteins such as CapZ regulate filament length. Severing proteins like cofilin increase turnover.

Crosslinkers and bundlers such as filamin, alpha-actinin, and fascin organize filaments into networks or bundles. Myosins (notably myosin II) generate force on actin filaments, driving contractility and cargo movement.

Actin dynamics are regulated by signaling pathways, notably Rho family GTPases (Rho, Rac, Cdc42) that coordinate ABP activities during processes such as cell migration, cytokinesis, and endocytosis. The spatial and temporal control of actin-interacting proteins underlies changes in cell shape and mechanics.

Actin-interacting proteins are studied through biochemical assays, fluorescence and electron microscopy, and structural biology, providing insights into polymerization rates, filament stability, and the architectures of actin networks. Dysregulation of actin interactions is associated with diseases including cancer metastasis, cardiomyopathies, and neurodegenerative disorders.