Aim44p regulates phosphorylation of Hof1p to promote contractile ring closure during cytokinesis in budding yeast

Mol Biol Cell. 2014 Mar;25(6):753-62. doi: 10.1091/mbc.E13-06-0317. Epub 2014 Jan 22.

Abstract

Whereas actomyosin and septin ring organization and function in cytokinesis are thoroughly described, little is known regarding the mechanisms by which the actomyosin ring interacts with septins and associated proteins to coordinate cell division. Here we show that the protein product of YPL158C, Aim44p, undergoes septin-dependent recruitment to the site of cell division. Aim44p colocalizes with Myo1p, the type II myosin of the contractile ring, throughout most of the cell cycle. The Aim44p ring does not contract when the actomyosin ring closes. Instead, it forms a double ring that associates with septin rings on mother and daughter cells after cell separation. Deletion of AIM44 results in defects in contractile ring closure. Aim44p coimmunoprecipitates with Hof1p, a conserved F-BAR protein that binds both septins and type II myosins and promotes contractile ring closure. Deletion of AIM44 results in a delay in Hof1p phosphorylation and altered Hof1p localization. Finally, overexpression of Dbf2p, a kinase that phosphorylates Hof1p and is required for relocalization of Hof1p from septin rings to the contractile ring and for Hof1p-triggered contractile ring closure, rescues the cytokinesis defect observed in aim44 cells. Our studies reveal a novel role for Aim44p in regulating contractile ring closure through effects on Hof1p.

Publication types

  • Research Support, American Recovery and Reinvestment Act
  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cytokinesis / genetics*
  • Gene Deletion
  • Gene Expression Regulation, Fungal*
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Microtubule-Associated Proteins / genetics*
  • Microtubule-Associated Proteins / metabolism
  • Myosin Heavy Chains / genetics
  • Myosin Heavy Chains / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Transport
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Septins / genetics*
  • Septins / metabolism
  • Signal Transduction

Substances

  • Aim44 protein, S cerevisiae
  • Cell Cycle Proteins
  • HOF1 protein, S cerevisiae
  • Intracellular Signaling Peptides and Proteins
  • MYO1 protein, S cerevisiae
  • Microtubule-Associated Proteins
  • Saccharomyces cerevisiae Proteins
  • DBF2 protein, S cerevisiae
  • Protein-Serine-Threonine Kinases
  • Septins
  • Myosin Heavy Chains