Septins: Cytoskeletal Filaments with Structural and Regulatory Functions

Dubbed as the fourth component of the cytoskeleton, septins comprise a network of nonpolar hetero-polymeric filaments, which assemble in a guanosine nucleotide-dependent manner. Septins are structurally and functionally interdependent with cell membranes, microtubules, and actin microfilaments. The primary function of septins is to control the spatial organization of membrane and cytoplasmic proteins by forming diffusion barriers and scaffolds. Thus, septins play key structural and regulatory roles in many of the functions and processes of the eukaryotic cell. Importantly, aberrations in septin expression and function are linked to the pathogenesis of many disease states.