Fig. 2.

Septin assembly in yeast and metazoa. a Septin assembly in yeast, Cdc42-dependent septin assembly. In yeast, assembly of the septin ring appears to have at least three steps: septin recruitment, septin ring assembly and septin ring maturation. Cdc42-GTP was required for the whole process of septin collar formation, which depends on activated Cdc42p and at least two partially redundant effector Gic1p and Gic2p. After septin recruitment, Cdc42, its GAPs (Rga1, Rga2 and Bem3), Cla4p, Gin4p, Elm1p, NAP1p and Bni1p are all required for septin ring assembly and maturation. Siz1p-related septin sumoylation is also involved in septin recruitment. b Metazoan septin assembly. Borg3, a CRIB motif containing protein and a Cdc42 effector, is required for metazoan septin assembly. Anillin, a conserved family of pleckstrin homology (PH)-domain proteins, is required for spatial control of metazoan septin organization. A Rho-guanine nucleotide exchange factor (GEF) SA-RhoGEF and a Rho effector Rhotekin are also involved in septin assembly. Whether the phosphorylation and/or sumoylation of septin could regulate septin assembly is still unknown