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  • The EMBO Journal (2009) 28, 3117 - 3131
  • doi:10.1038/emboj.2009.252

Published online: 27 August 2009

Fission yeast IQGAP arranges actin filaments into the cytokinetic contractile ring

Masak Takaine1, Osamu Numata1 and Kentaro Nakano1

  1. Department of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan

Correspondence to:

Masak Takaine, Department of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki 305-8577, Japan. Tel.:/Fax: +81 029 853 4530; E-mail: masaktakaine@gmail.com

Kentaro Nakano, Department of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennohdai, Tsukuba, Ibaraki 305-8577, Japan. Tel.:/Fax: +81 029 853 6642; E-mail: knakano@biol.tsukuba.ac.jp

Received 22 February 2009; Accepted 27 July 2009

The contractile ring (CR) consists of bundled actin filaments and myosin II; however, the actin-bundling factor remains elusive. We show that the fission yeast Schizosaccharomyces pombe IQGAP Rng2 is involved in the generation of CR F-actin and required for its arrangement into a ring. An N-terminal fragment of Rng2 is necessary for the function of Rng2 and is localized to CR F-actin. In vitro the fragment promotes actin polymerization and forms linear arrays of F-actin, which are resistant to the depolymerization induced by the actin-depolymerizing factor Adf1. Our findings indicate that Rng2 is involved in the generation of CR F-actin and simultaneously bundles the filaments and regulates its dynamics by counteracting the effects of Adf1, thus enabling the reconstruction of CR F-actin bundles, which provides an insight into the physical properties of the building blocks that comprise the CR.

  • Keywords:

    • actin cytoskeleton,
    • contractile ring,
    • cytokinesis,
    • fission yeast,
    • IQGAP