Fission yeast IQGAP arranges actin filaments into the cytokinetic contractile ring.
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.
Takaine
Masak
M
Department of Structural Biosciences, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan. masaktakaine@gmail.com
Numata
Osamu
O
Nakano
Kentaro
K
D008841:Actin Cytoskeleton / Q000378:metabolism*; D000199:Actins / Q000378:metabolism; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D048749:Cytokinesis / Q000235:genetics / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D011485:Protein Binding; D011817:Rabbits; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013050:Spectrometry, Fluorescence; D013696:Temperature
D000199:Actins; D018797:Cell Cycle Proteins; D020690:GTPase-Activating Proteins; C114172:Rng2 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins