Details

Autor(en) / Beteiligte

• Takaine, Masak
• Numata, Osamu
• Nakano, Kentaro

Titel

Fission yeast IQGAP maintains F‐actin‐independent localization of myosin‐II in the contractile ring

Ist Teil von

• Genes to cells : devoted to molecular & cellular mechanisms, 2014-02, Vol.19 (2), p.161-176

Ort / Verlag

England: Wiley Subscription Services, Inc

Erscheinungsjahr

2014

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• During cytokinesis in many eukaryotic cells, myosin‐II concentrates at the equatorial cortex with actin filaments (F‐actin) and is supposed to generate forces to divide the cell into two, which is called the contractile ring (CR) hypothesis. Several lines of evidence indicate that the myosin‐II is recruited independently of F‐actin and interacts specifically with the equatorial F‐actin. Molecular details of these mechanisms are still unknown. We used the fission yeast Schizosaccharomyces pombe to investigate the regulation of myosin‐II localization. We demonstrate that the CR myosin‐II was composed of F‐actin‐dependent and ‐independent fractions by simultaneously observing F‐actin and myosin. The F‐actin‐independent fraction was visualized as cortical dots in the absence of F‐actin. IQGAP Rng2, an indispensable element of CR, was implicated in maintenance of the F‐actin‐independent fraction of myosin‐II, whereas anillin Mid1 was required for assembly but not for maintenance of the fraction. In the CR of the rng2 mutant, myosin‐II was less concentrated, unstable, and nonhomogeneous, which often resulted in cytokinesis failure. These results suggest that Rng2 tethers myosin‐II to the cortex along the CR independently of F‐actin to provide a sufficient concentration. The robust localization of myosin‐II would ensure successful cytokinesis.