The J-protein family: modulating protein assembly, disassembly and translocation

EMBO Rep. 2004 Jun;5(6):567-71. doi: 10.1038/sj.embor.7400172.


DnaJ is a molecular chaperone and the prototypical member of the J-protein family. J proteins are defined by the presence of a J domain that can regulate the activity of 70-kDa heat-shock proteins. Sequence analysis on the genome of Saccharomyces cerevisiae has revealed 22 proteins that establish four distinguishing structural features of the J domain: predicted helicity in segments I-IV, precisely placed interhelical contact residues, a lysine-rich surface on helix II and placement of the diagnostic sequence HPD between the predicted helices II and III. We suggest that this definition of the J-protein family could be used for other genome-wide studies. In addition, three J-like proteins were identified in yeast that contain regions closely resembling a J domain, but in which the HPD motif is non-conservatively replaced. We suggest that J-like proteins might function to regulate the activity of bona fide J proteins during protein translocation, assembly and disassembly.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Genome, Fungal
  • Heat-Shock Proteins / classification
  • Heat-Shock Proteins / physiology*
  • Molecular Chaperones / classification
  • Molecular Chaperones / physiology*
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / classification
  • Saccharomyces cerevisiae Proteins / physiology*
  • Sequence Alignment


  • Heat-Shock Proteins
  • Molecular Chaperones
  • Saccharomyces cerevisiae Proteins