In vitro contraction of cytokinetic ring depends on myosin II but not on actin dynamics.

Mithilesh Mishra, Jun Kashiwazaki, Tomoko Takagi, Ramanujam Srinivasan, Yinyi Huang, Mohan K Balasubramanian, Issei Mabuchi

Nature cell biology 2013 Jul

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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.

Citation

Mithilesh Mishra, Jun Kashiwazaki, Tomoko Takagi, Ramanujam Srinivasan, Yinyi Huang, Mohan K Balasubramanian, Issei Mabuchi. In vitro contraction of cytokinetic ring depends on myosin II but not on actin dynamics. Nature cell biology. 2013 Jul;15(7):853-9