Cell cycle-dependent phosphorylation of IQGAP is involved in assembly and stability of the contractile ring in fission yeast

Biochem Biophys Res Commun. 2021 Jan 1:534:1026-1032. doi: 10.1016/j.bbrc.2020.10.043. Epub 2020 Oct 29.


Cytokinesis is the final step in cell division and is driven by the constriction of the medial actomyosin-based contractile ring (CR) in many eukaryotic cells. In the fission yeast Schizosaccharomyces pombe, the IQGAP-like protein Rng2 is required for assembly and constriction of the CR, and specifically interacts with actin filaments (F-actin) in the CR after anaphase. However, the mechanism that timely activates Rng2 has not yet been elucidated. We herein tested the hypothesis that the cytokinetic function of Rng2 is regulated by phosphorylation by examining phenotypes of a series of non-phosphorylatable and phosphomimetic rng2 mutant strains. In phosphomimetic mutant cells, F-actin in the CR was unstable. Genetic analyses indicated that phosphorylated Rng2 was involved in CR assembly in cooperation with myosin-II, whereas the phosphomimetic mutation attenuated the localization of Rng2 to CR F-actin. The present results suggest that Rng2 is phosphorylated during CR assembly and then dephosphorylated, which enhances the interaction between Rng2 and CR F-actin to stabilize the ring, thereby ensuring secure cytokinesis.

Keywords: Cell cycle; Cytokinesis; Fission yeast; IQGAP; Phosphoregulation; Rng2; The contractile ring.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism
  • Actins / metabolism
  • Cell Cycle
  • Cell Cycle Proteins / metabolism*
  • Cytokinesis
  • GTPase-Activating Proteins / metabolism*
  • Phosphorylation
  • Schizosaccharomyces / cytology
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / metabolism*
  • ras GTPase-Activating Proteins / metabolism*


  • Actins
  • Cell Cycle Proteins
  • GTPase-Activating Proteins
  • IQ motif containing GTPase activating protein 1
  • Rng2 protein, S pombe
  • Schizosaccharomyces pombe Proteins
  • ras GTPase-Activating Proteins