FIGURE 1.

Septins during cytokinesis. (A) At anaphase RhoA is activated at the midzone (red shadow). (B) At early telophase septins (green) are recruited to furrow by anillin (pink), and during furrow constriction promote extrusion of plasma membrane tubules. (C) After ingression septins reorganize into a double ring and support the formation of secondary ingression sites by dictating the relocalization of anillin and actomyosin (purple). At the same time SEPT9 locally activates Tsg101 (light blue). Initial recruitment of ESCRTI to the midbody is not depicted for clarity reasons. (D) Recruitment of ESCRTIII (red) occurs concomitantly with the disappearance of septin double rings. PI(4,5)P₂ (dark grey) builds up early at the cleavage furrow, and might also become concentrated at the midbody ring. PI(4,5)P₂ is hydrolyzed upon arrival of OCRL (blue) at the ICB. Prior to abscission a pool of PI(3)P (yellow) is generated at the midbody that likely supports ESCRT assembly.