A central chaperone-like role for 14-3-3 proteins in human cells

  • Mol Cell. 2023 Mar 16;83(6):974-993.e15. doi: 10.1016/j.molcel.2023.02.018.
Dmitri Segal  1 ,  Stefan Maier  2 ,  Giovanni J Mastromarco  3 ,  Wesley Wei Qian  4 ,  Syed Nabeel-Shah  1 ,  Hyunmin Lee  5 ,  Gaelen Moore  3 ,  Jessica Lacoste  1 ,  Brett Larsen  2 ,  Zhen-Yuan Lin  2 ,  Abeeshan Selvabaskaran  6 ,  Karen Liu  6 ,  Craig Smibert  7 ,  Zhaolei Zhang  8 ,  Jack Greenblatt  1 ,  Jian Peng  4 ,  Hyun O Lee  3 ,  Anne-Claude Gingras  9 ,  Mikko Taipale  10
Affiliations
  • 1. Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada.
  • 2. Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON M5G 1X5, Canada.
  • 3. Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
  • 4. Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
  • 5. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5S 3G4, Canada.
  • 6. Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada.
  • 7. Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada.
  • 8. Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Computer Science, University of Toronto, Toronto, ON M5S 3G4, Canada.
  • 9. Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON M5G 1X5, Canada. Electronic address: [email protected].
  • 10. Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada. Electronic address: [email protected].
PMID: 36931259 DOI: 10.1016/j.molcel.2023.02.018
Abstract

14-3-3 proteins are highly conserved regulatory proteins that interact with hundreds of structurally diverse clients and act as central hubs of signaling networks. However, how 14-3-3 paralogs differ in specificity and how they regulate client protein function are not known for most clients. Here, we map the interactomes of all human 14-3-3 paralogs and systematically characterize the effect of disrupting these interactions on client localization. The loss of 14-3-3 binding leads to the coalescence of a large fraction of clients into discrete foci in a client-specific manner, suggesting a central chaperone-like function for 14-3-3 proteins. Congruently, the engraftment of 14-3-3 binding motifs to nonclients can suppress their aggregation or phase separation. Finally, we show that 14-3-3s negatively regulate the localization of the RNA-binding protein SAMD4A to cytoplasmic granules and inhibit its activity as a translational repressor. Our work suggests that 14-3-3s have a more prominent role as chaperone-like molecules than previously thought.

Keywords
14-3-3 proteins; affinity purification; aggregation; chaperones; functional proteomics; mass spectrometry; phase transitions; protein quality control; proximity-dependent biotinylation.