A memory system of negative polarity cues prevents replicative aging

Cell. 2014 Nov 20;159(5):1056-1069. doi: 10.1016/j.cell.2014.10.014. Epub 2014 Nov 13.

Abstract

Cdc42 is a highly conserved master regulator of cell polarity. Here, we investigated the mechanism by which yeast cells never re-establish polarity at cortical sites (cytokinesis remnants [CRMs]) that have previously supported Cdc42-mediated growth as a paradigm to mechanistically understand how Cdc42-inhibitory polarity cues are established. We revealed a two-step mechanism of loading the Cdc42 antagonist Nba1 into CRMs to mark these compartments as refractory for a second round of Cdc42 activation. Our data indicate that Nba1 together with a cortically tethered adaptor protein confers memory of previous polarization events to translate this spatial legacy into a biochemical signal that ensures the local singularity of Cdc42 activation. "Memory loss" mutants that repeatedly use the same polarity site over multiple generations display nuclear segregation defects and a shorter lifespan. Our work thus established CRMs as negative polarity cues that prevent Cdc42 reactivation to sustain the fitness of replicating cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asymmetric Cell Division
  • Cell Cycle Proteins / metabolism
  • Cell Polarity
  • Guanine Nucleotide Exchange Factors / metabolism
  • Membrane Proteins / metabolism
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • cdc42 GTP-Binding Protein, Saccharomyces cerevisiae / metabolism*

Substances

  • CDC24 protein, S cerevisiae
  • Cell Cycle Proteins
  • Guanine Nucleotide Exchange Factors
  • Membrane Proteins
  • Nba1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • cdc42 GTP-Binding Protein, Saccharomyces cerevisiae