SEPTIN2 is a filament-forming cytoskeletal GTPase that plays critical roles in multiple cellular processes. The protein forms complexes with other septins, including SEPTIN6, SEPTIN7, and SEPTIN12, which are essential for cytoskeletal organization and cell division 1. In spermatogenesis, SEPTIN2 forms filamentous structures at the sperm annulus required for sperm tail integrity and motility, and mediates head-tail junction through interactions with SUN5 and SEPTIN12 2. The protein regulates actin cytoskeleton organization and controls cell morphology by interacting with ARHGAP25 to suppress lamellipodia formation 3. SEPTIN2 is subject to post-translational modifications that affect its function: S-nitrosylation at cysteine 111 drives aortic aneurysm development by activating the TIAM1-RAC1 inflammatory pathway 4, while folate-dependent methylation is crucial for GTP binding activity and cilium formation during neural tube closure 1. In disease contexts, SEPTIN2 acts as a tumor suppressor in glioblastoma, where its knockdown inhibits cell proliferation through p53/p21 and MEK/ERK pathways 5, and suppresses inflammatory macrophage activation by regulating ER stress responses 6. Hypoxia-induced downregulation of SEPTIN2 impairs male fertility by disrupting spermatogonial proliferation through PP2A-mediated AKT dephosphorylation 7.