A Zpr1 co-chaperone mediates folding of eukaryotic translation elongation factor 1A via a GTPase cycle

Mol Cell. 2023 Sep 7;83(17):3108-3122.e13. doi: 10.1016/j.molcel.2023.07.028. Epub 2023 Aug 18.

Abstract

General protein folding is mediated by chaperones that utilize ATP hydrolysis to regulate client binding and release. Zinc-finger protein 1 (Zpr1) is an essential ATP-independent chaperone dedicated to the biogenesis of eukaryotic translation elongation factor 1A (eEF1A), a highly abundant GTP-binding protein. How Zpr1-mediated folding is regulated to ensure rapid Zpr1 recycling remains an unanswered question. Here, we use yeast genetics and microscopy analysis, biochemical reconstitution, and structural modeling to reveal that folding of eEF1A by Zpr1 requires GTP hydrolysis. Furthermore, we identify the highly conserved altered inheritance of mitochondria 29 (Aim29) protein as a Zpr1 co-chaperone that recognizes eEF1A in the GTP-bound, pre-hydrolysis conformation. This interaction dampens Zpr1⋅eEF1A GTPase activity and facilitates client exit from the folding cycle. Our work reveals that a bespoke ATP-independent chaperone system has mechanistic similarity to ATPase chaperones but unexpectedly relies on client GTP hydrolysis to regulate the chaperone-client interaction.

Keywords: chaperones; eEF1A; heat-shock response; integrated stress response; protein folding; protein homeostasis; proteostasis; translation elongation factors.

Publication types

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

MeSH terms

  • Adenosine Triphosphate
  • Carrier Proteins* / metabolism
  • GTP Phosphohydrolases* / genetics
  • Guanosine Triphosphate
  • Humans
  • Molecular Chaperones* / genetics
  • Peptide Elongation Factors* / metabolism
  • Protein Folding
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins* / metabolism

Substances

  • Adenosine Triphosphate
  • GTP Phosphohydrolases
  • Guanosine Triphosphate
  • Molecular Chaperones
  • Peptide Elongation Factors
  • ZPR1 protein, S cerevisiae
  • Carrier Proteins
  • Saccharomyces cerevisiae Proteins