Förmins

Förmins are a family of proteins known for their pivotal role in the regulation of the actin cytoskeleton within eukaryotic cells. They are characterized by the presence of formin homology domains, primarily the FH1 and FH2 domains, which enable them to nucleate and elongate actin filaments. These proteins are involved in various cellular processes, including cell shape modulation, polarity, migration, and division.

Typically, formins function as dimers, forming a doughnut-shaped FH2 domain that associates with the growing end of actin filaments. The FH1 domain interacts with profilin-actin complexes to supply monomers for filament elongation. Through these mechanisms, formins facilitate the formation of linear actin filaments necessary for cellular structures such as filopodia, lamellipodia, and stress fibers.

Formins are regulated through multiple mechanisms, including autoinhibition and interactions with Rho family GTPases, which activate formins by relieving autoinhibition. Different formin isoforms are expressed in various tissues and cell types, each contributing to specific cellular functions.

Research has shown that dysregulation of formins is associated with various diseases, including cancer, where aberrant cell migration and invasion occur. Consequently, formins are considered important targets for understanding cytoskeletal dynamics and developing therapeutic interventions.

Overall, formins are essential actin-nucleating factors that orchestrate the organization of the cytoskeleton, influencing cellular morphology, motility, and function.