Competition in the chaperone-client network subordinates cell-cycle entry to growth and stress

Life Sci Alliance. 2019 Apr 15;2(2):e201800277. doi: 10.26508/lsa.201800277. Print 2019 Apr.


The precise coordination of growth and proliferation has a universal prevalence in cell homeostasis. As a prominent property, cell size is modulated by the coordination between these processes in bacterial, yeast, and mammalian cells, but the underlying molecular mechanisms are largely unknown. Here, we show that multifunctional chaperone systems play a concerted and limiting role in cell-cycle entry, specifically driving nuclear accumulation of the G1 Cdk-cyclin complex. Based on these findings, we establish and test a molecular competition model that recapitulates cell-cycle-entry dependence on growth rate. As key predictions at a single-cell level, we show that availability of the Ydj1 chaperone and nuclear accumulation of the G1 cyclin Cln3 are inversely dependent on growth rate and readily respond to changes in protein synthesis and stress conditions that alter protein folding requirements. Thus, chaperone workload would subordinate Start to the biosynthetic machinery and dynamically adjust proliferation to the growth potential of the cell.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CDC28 Protein Kinase, S cerevisiae / metabolism
  • Cell Enlargement*
  • Cell Nucleolus / metabolism
  • Cell Size*
  • Cyclin-Dependent Kinases / metabolism
  • Cyclins / metabolism
  • G1 Phase Cell Cycle Checkpoints / physiology*
  • HSP40 Heat-Shock Proteins / metabolism
  • Heat-Shock Response / physiology*
  • Models, Molecular
  • Molecular Chaperones / metabolism*
  • S Phase Cell Cycle Checkpoints / physiology
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae Proteins / metabolism
  • Salt Stress / physiology*


  • CLN3 protein, S cerevisiae
  • Cyclins
  • HSP40 Heat-Shock Proteins
  • Molecular Chaperones
  • Saccharomyces cerevisiae Proteins
  • YDJ1 protein, S cerevisiae
  • CDC28 Protein Kinase, S cerevisiae
  • Cyclin-Dependent Kinases