The Rim15-endosulfine-PP2ACdc55 signalling module regulates entry into gametogenesis and quiescence via distinct mechanisms in budding yeast

PLoS Genet. 2014 Jun 26;10(6):e1004456. doi: 10.1371/journal.pgen.1004456. eCollection 2014 Jun.


Quiescence and gametogenesis represent two distinct survival strategies in response to nutrient starvation in budding yeast. Precisely how environmental signals are sensed by yeast cells to trigger quiescence and gametogenesis is not fully understood. A conserved signalling module consisting of Greatwall kinase, Endosulfine and Protein Phosphatase PP2ACdc55 proteins regulates entry into mitosis in Xenopus egg extracts and meiotic maturation in flies. We report here that an analogous signalling module consisting of the serine-threonine kinase Rim15, the Endosulfines Igo1 and Igo2 and the Protein Phosphatase PP2ACdc55, regulates entry into both quiescence and gametogenesis in budding yeast. PP2ACdc55 inhibits entry into gametogenesis and quiescence. Rim15 promotes entry into gametogenesis and quiescence by converting Igo1 into an inhibitor of PP2ACdc55 by phosphorylating at a conserved serine residue. Moreover, we show that the Rim15-Endosulfine-PP2ACdc55 pathway regulates entry into quiescence and gametogenesis by distinct mechanisms. In addition, we show that Igo1 and Igo2 are required for pre-meiotic autophagy but the lack of pre-meiotic autophagy is insufficient to explain the sporulation defect of igo1Δ igo2Δ cells. We propose that the Rim15-Endosulfine-PP2ACdc55 signalling module triggers entry into quiescence and gametogenesis by regulating dephosphorylation of distinct substrates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autophagy / genetics
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism
  • Gametogenesis / genetics
  • Miosis / genetics
  • Protein Kinases / genetics*
  • Protein Kinases / metabolism
  • Protein Phosphatase 2 / genetics*
  • Protein Phosphatase 2 / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Signal Transduction


  • Cell Cycle Proteins
  • Igo1 protein, S cerevisiae
  • Igo2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Protein Kinases
  • Rim15 protein, S cerevisiae
  • PPH21 protein, S cerevisiae
  • Protein Phosphatase 2