Pom1 and cell size homeostasis in fission yeast

Cell Cycle. 2013 Oct 1;12(19):3228-36. doi: 10.4161/cc.26462. Epub 2013 Sep 12.


Cells sense their size and use this information to coordinate cell division with cell growth to maintain a constant cell size within a given population. A model has been proposed for cell size control in the rod-shaped cells of the fission yeast, Schizosaccharomyces pombe. This involves a protein localized to the cell ends, which inhibits mitotic activators in the middle of the cell in a cell size-dependent manner. This protein, Pom1, along with another tip-localized protein, Nif1, have been implicated as direct sensors of cell size controlling the onset of mitosis. Here we have investigated cell size variability and size homeostasis at the G 2/M transition, focusing on the role of pom1 and nif1. Cells deleted for either of these 2 genes show wild-type size homeostasis both in size variability analyses and size homeostasis experiments. This indicates that these genes do not have a critical role as direct cell size sensors in the control mechanism. Cell size homeostasis also seems to be independent of Cdc2-Tyr15 phosphorylation, suggesting that the size sensing mechanism in fission yeast may act through an unidentified pathway regulating CDK activity by an unknown mechanism.

Keywords: Pom1; cell cycle; cell size control; cell size variability; fission yeast; growth rate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CDC2 Protein Kinase / metabolism
  • Cell Division
  • Cell Size
  • G2 Phase
  • Homeostasis
  • Microfluidic Analytical Techniques
  • Phosphorylation
  • Protein Kinases / metabolism*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism


  • NIF1 protein, S pombe
  • Repressor Proteins
  • Schizosaccharomyces pombe Proteins
  • Protein Kinases
  • Pom1 protein, S pombe
  • CDC2 Protein Kinase
  • cdc2 protein, S pombe