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Species‐Specific Hsp70 and Hsp100 Teamwork in Thermotolerance and Protein Disaggregation
Author(s) -
Miot Marika,
Reidy Michael,
Doyle Shan,
Hoskins Joel,
Johnston Danielle,
Masison Daniel,
Wickner Sue
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.lb60
Subject(s) - clpb , chaperone (clinical) , biology , protein aggregation , heat shock protein , biochemistry , microbiology and biotechnology , gene , medicine , pathology
Cells possess molecular chaperones and proteases to counteract the toxic effects of environmental stresses. The chaperone Hsp104 in yeast and its homolog ClpB in E. coli possess the unique ability to solubilize and refold aggregated proteins in cooperation with the Hsp70/DnaK chaperone system. The action of Hsp104 and ClpB in promoting thermotolerance is species specific: Hsp104 cannot function in bacteria and ClpB cannot act in yeast. To determine the regions of Hsp104 and ClpB necessary for this specificity, we tested chimeras of Hsp104 and ClpB in vivo and in vitro. We show that the Hsp104 and ClpB middle‐domains dictate the species specificity of Hsp104/ClpB for cell survival at high temperature. In protein reactivation assays in vitro, we show that the region responsible for the specificity is within helix 2 and helix 3 of the middle‐domain. In a bacterial two‐hybrid assay, DnaK interacts with ClpB and with chimeras that have the ClpB middle domain. Our results suggest that the interaction between Hsp70/DnaK and helices 2 and 3 of the middle‐domain of Hsp104/ClpB determines the specificity required for protein disaggregation both in vivo and in vitro, as well as for cellular thermotolerance.