a) schematic of septin molecule with GTP binding domain to one side and the N and C termini of the polypeptide chain to the other b) schematic of septin heterohexameric complex (of human septins), where different septins bind to each other via their GTP binding domains or via the N and C termini. Note the symetry of the complex c) schematic how septin complexes could align to form septin filaments