Slt2p phosphorylation induces cyclin C nuclear-to-cytoplasmic translocation in response to oxidative stress

Mol Biol Cell. 2014 Apr;25(8):1396-407. doi: 10.1091/mbc.E13-09-0550. Epub 2014 Feb 19.

Abstract

The yeast C-type cyclin represses the transcription of genes required for the stress response and meiosis. To relieve this repression, cyclin C undergoes nuclear-to-cytoplasmic translocation in response to many stressors, including hydrogen peroxide, where it is destroyed by ubiquitin-mediated proteolysis. Before its destruction, cyclin C promotes stress-induced mitochondrial fission and programmed cell death, indicating that relocalization is an important cell fate regulator. Here we show that cyclin C cytoplasmic translocation requires the cell wall integrity (CWI) mitogen-activated protein kinase Slt2p, its pseudokinase paralogue, Kdx1p, and an associating transcription factor, Ask10p. Furthermore, Slt2p and Kdx1p regulate cyclin C stability through different but required mechanisms. Slt2p associates with, and directly phosphorylates, cyclin C at Ser-266. Eliminating or mimicking phosphorylation at this site restricts or enhances cyclin C cytoplasmic translocation and degradation, respectively. Conversely, Kdx1p does not bind cyclin C but instead coimmunoprecipitates with Ask10p, a transcription factor previously identified as a regulator of cyclin C destruction. These results reveal a complex regulatory circuitry involving both downstream effectors of the CWI mitogen-activated protein kinase signal transduction pathway to target the relocalization and consequent destruction of a single transcriptional repressor.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics
  • Bacterial Proteins
  • Cyclin C / metabolism*
  • Gene Expression Regulation, Fungal / drug effects
  • Hydrogen Peroxide / pharmacology
  • Immunoprecipitation
  • Luminescent Proteins
  • MAP Kinase Signaling System
  • Mitochondria / metabolism
  • Mitochondrial Dynamics / drug effects*
  • Mitogen-Activated Protein Kinases / metabolism*
  • Nuclear Proteins / metabolism
  • Oxidative Stress*
  • Phosphorylation
  • Protein Transport
  • RNA-Binding Proteins
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Transcription Factors / metabolism

Substances

  • Ask10 protein, S cerevisiae
  • Bacterial Proteins
  • Cyclin C
  • Luminescent Proteins
  • MLP1 protein, S cerevisiae
  • Nuclear Proteins
  • RNA-Binding Proteins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • yellow fluorescent protein, Bacteria
  • Hydrogen Peroxide
  • Mitogen-Activated Protein Kinases
  • SLT2 protein, S cerevisiae