Forminmediated

Formin-mediated refers to processes governed by formin proteins, a family of actin-nucleating and elongating factors that promote the assembly of linear actin filaments. Formins help shape the cytoskeleton, contributing to structures such as stress fibers, filopodia, and the contractile ring during cytokinesis, and they can coordinate actin dynamics with vesicle trafficking and microtubules.

Formins typically function as dimers containing regulatory regions and a conserved FH2 domain that nucleates actin and remains associated with the growing barbed end to promote processive elongation. The adjacent FH1 proline-rich region binds profilin–actin, supplying monomers for rapid filament growth. Activity is controlled by autoinhibition through the DID–DAD interaction and relieved by Rho family GTPases, phosphorylation, and partner proteins.

Formins are divided into subfamilies such as DIAPH/mDia, FHOD, and INF, which differ in localization and regulation. They primarily generate unbranched filaments, complementing the branched networks produced by the Arp2/3 complex, and some formins also influence microtubule dynamics and membrane remodeling.

Physiologically, formin-mediated actin assembly supports cell division, polarity, migration, and development. Disruption or mutation of specific formins can contribute to diseases including cancer metastasis, kidney disorders, and neurodevelopmental conditions, depending on the tissue context.

Research on formin activity employs in vitro nucleation assays, single-molecule imaging, and genetic models to understand their roles in morphogenesis, cell behavior, and disease.