Comprehensive interactome profiling of the human Hsp70 network highlights functional differentiation of J domains

Mol Cell. 2021 Jun 17;81(12):2549-2565.e8. doi: 10.1016/j.molcel.2021.04.012. Epub 2021 May 5.


Hsp70s comprise a deeply conserved chaperone family that has a central role in maintaining protein homeostasis. In humans, Hsp70 client specificity is provided by 49 different co-factors known as J domain proteins (JDPs). However, the cellular function and client specificity of JDPs have largely remained elusive. We have combined affinity purification-mass spectrometry (AP-MS) and proximity-dependent biotinylation (BioID) to characterize the interactome of all human JDPs and Hsp70s. The resulting network suggests specific functions for many uncharacterized JDPs, and we establish a role of conserved JDPs DNAJC9 and DNAJC27 in histone chaperoning and ciliogenesis, respectively. Unexpectedly, we find that the J domain of DNAJC27 but not of other JDPs can fully replace the function of endogenous DNAJC27, suggesting a previously unappreciated role for J domains themselves in JDP specificity. More broadly, our work expands the role of the Hsp70-regulated proteostasis network and provides a platform for further discovery of JDP-dependent functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • HEK293 Cells
  • HSP40 Heat-Shock Proteins / metabolism
  • HSP40 Heat-Shock Proteins / physiology*
  • HSP70 Heat-Shock Proteins / metabolism
  • HSP70 Heat-Shock Proteins / physiology*
  • HeLa Cells
  • Humans
  • Molecular Chaperones / metabolism
  • Protein Binding
  • Protein Domains
  • Protein Interaction Domains and Motifs / physiology*
  • rab GTP-Binding Proteins / metabolism


  • DNAJC9 protein, human
  • HSP40 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins
  • Molecular Chaperones
  • DNAJC27 protein, human
  • rab GTP-Binding Proteins