title: In vitro contraction of cytokinetic ring depends on myosin II but not on actin dynamics.
abstract: Cytokinesis in many eukaryotes involves the contraction of an actomyosin-based contractile ring. However, the detailed mechanism of contractile ring contraction is not fully understood. Here, we establish an experimental system to study contraction of the ring to completion in vitro. We show that the contractile ring of permeabilized fission yeast cells undergoes rapid contraction in an ATP- and myosin-II-dependent manner in the absence of other cytoplasmic constituents. Surprisingly, neither actin polymerization nor its disassembly is required for contraction of the contractile ring, although addition of exogenous actin-crosslinking proteins blocks ring contraction. Using contractile rings generated from fission yeast cytokinesis mutants, we show that not all proteins required for assembly of the ring are required for its contraction in vitro. Our work provides the beginnings of the definition of a minimal contraction-competent cytokinetic ring apparatus.
authors.affiliation: Temasek Life Sciences Laboratory, The National University of Singapore, 1 Research Link, Singapore 117604, Singapore.
authors.forename: Mithilesh
authors.initials: M
authors.lastname: Mishra
authors.forename: Jun
authors.initials: J
authors.lastname: Kashiwazaki
authors.forename: Tomoko
authors.initials: T
authors.lastname: Takagi
authors.forename: Ramanujam
authors.initials: R
authors.lastname: Srinivasan
authors.forename: Yinyi
authors.initials: Y
authors.lastname: Huang
authors.forename: Mohan K
authors.initials: MK
authors.lastname: Balasubramanian
authors.forename: Issei
authors.initials: I
authors.lastname: Mabuchi
mesh_terms: D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism; D048749:Cytokinesis / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D024462:Myosin Type II / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000166:cytology* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*
chemical_list: D000199:Actins; D029702:Schizosaccharomyces pombe Proteins; D049452:Green Fluorescent Proteins; D000255:Adenosine Triphosphate; D024462:Myosin Type II