Anillin acts as a bifunctional linker coordinating midbody ring biogenesis during cytokinesis.
Animal cell cytokinesis proceeds via constriction of an actomyosin-based contractile ring (CR) [1, 2]. Upon reaching a diameter of ~1 μm [3], a midbody ring (MR) forms to stabilize the intercellular bridge until abscission [4-6]. How MR formation is coupled to CR closure and how plasma membrane anchoring is maintained at this key transition is unknown. Time-lapse microscopy of Drosophila S2 cells depleted of the scaffold protein Anillin [7-9] revealed that Anillin is required for complete closure of the CR and formation of the MR. Truncation analysis revealed that Anillin N termini connected with the actomyosin CR and supported formation of stable MR-like structures, but these could not maintain anchoring of the plasma membrane. Conversely, Anillin C termini failed to connect with the CR or MR but recruited the septin Peanut to ectopic structures at the equatorial cortex. Peanut depletion mimicked truncation of the Anillin C terminus, resulting in MR-like structures that failed to anchor the membrane. These data demonstrate that Anillin coordinates the transition from CR to MR and that it does so by linking two distinct cortical cytoskeletal elements. One apparently acts as the core structural template for MR assembly, while the other ensures stable anchoring of the plasma membrane beyond the CR stage.
CHU Sainte-Justine Centre de Recherche, Centre de Cancérologie Charles Bruneau, 3175 Chemin de la Côte Ste-Catherine, Montréal, Québec H3T 1C5, Canada.
Amel
A
Kechad
Silvana
S
Jananji
Yvonne
Y
Ruella
Gilles R X
GR
Hickson
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D003285:Contractile Proteins / Q000502:physiology*; D048749:Cytokinesis; D029721:Drosophila Proteins / Q000378:metabolism / Q000502:physiology; D004331:Drosophila melanogaster / Q000166:cytology*; D008840:Microfilament Proteins / Q000378:metabolism / Q000502:physiology
D003285:Contractile Proteins; D029721:Drosophila Proteins; D008840:Microfilament Proteins; C095886:anillin; C087195:pnut protein, Drosophila