Alpha-actinin is required for tightly regulated remodeling of the actin cortical network during cytokinesis.
Localization of the actin crosslinking protein, alpha-actinin, to the cleavage furrow has been previously reported. However, its functions during cytokinesis remain poorly understood. We have analyzed the functions of alpha-actinin during cytokinesis by a combination of molecular manipulations and imaging-based techniques. alpha-actinin gradually dissipated from the cleavage furrow as cytokinesis progressed. Overexpression of alpha-actinin caused increased accumulation of actin filaments because of inhibition of actin turnover, leading to cytokinesis failure. Global depletion of alpha-actinin by siRNA caused a decrease in the density of actin filaments throughout the cell cortex, surprisingly inducing accelerated cytokinesis and ectopic furrows. Local ablation of alpha-actinin induced accelerated cytokinesis specifically at the site of irradiation. Neither overexpression nor depletion of alpha-actinin had an apparent effect on myosin II organization. We conclude that cytokinesis in mammalian cells requires tightly regulated remodeling of the cortical actin network mediated by alpha-actinin in coordination with actomyosin-based cortical contractions.
Mukhina
Svetlana
S
Mammalian Cell Biology Group, Temasek Life Sciences Laboratory, The National University of Singapore, 1 Research Link, 117604, Singapore.
Wang
Yu-Li
YL
Murata-Hori
Maki
M
D008841:Actin Cytoskeleton / Q000502:physiology*; D000185:Actinin / Q000502:physiology*; D000818:Animals; D002460:Cell Line; D048749:Cytokinesis / Q000502:physiology*; D051381:Rats
D000185:Actinin