Structural analysis of the ribosome-associated complex (RAC) reveals an unusual Hsp70/Hsp40 interaction

• Verfasst von: Fiaux Vogel, Jocelyne [VerfasserIn]
• Verfasst von: Horst, Janina [VerfasserIn]
• Verfasst von: Scior, Annika [VerfasserIn]
• Verfasst von: Preißler, Steffen [VerfasserIn]
• Verfasst von: Koplin, Ansgar [VerfasserIn]
• Verfasst von: Bukau, Bernd [VerfasserIn]
• Verfasst von: Deuerling, Elke [VerfasserIn]
• Titel: Structural analysis of the ribosome-associated complex (RAC) reveals an unusual Hsp70/Hsp40 interaction
• Verf.angabe: Jocelyne Fiaux, Janina Horst, Annika Scior, Steffen Preissler, Ansgar Koplin, Bernd Bukau, and Elke Deuerling
• E-Jahr: 2010
• Jahr: 29 January 2010
• Umfang: 8 S.
• Fussnoten: Online veröffentlicht am 17. November 2009 ; Gesehen am 23.10.2023
• Titel Quelle: Enthalten in: The journal of biological chemistry
• Ort Quelle: Bethesda, Md. : ASBMB Publications, 1905
• Jahr Quelle: 2010
• Band/Heft Quelle: 285(2010), 5, Seite 3227-3234
• ISSN Quelle: 1083-351X
• DOI: doi:10.1074/jbc.M109.075804
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Chaperones
• Sach-SW: Chaperones/Heat Shock
• Sach-SW: Chaperones/Protein Folding
• Sach-SW: Hsp40
• Sach-SW: Hsp70
• Sach-SW: Protein/Folding
• Sach-SW: Protein/Protein-Protein Interactions
• Sach-SW: Ribosome
• K10plus-PPN: 1867257769

Abstract

Yeast Zuotin and Ssz are members of the conserved Hsp40 and Hsp70 chaperone families, respectively, but compared with canonical homologs, they atypically form a stable heterodimer termed ribosome-associated complex (RAC). RAC acts as co-chaperone for another Hsp70 to assist de novo protein folding. In this study, we identified the molecular basis for the unusual Hsp70/Hsp40 pairing using amide hydrogen exchange (HX) coupled with mass spectrometry and mutational analysis. Association of Ssz with Zuotin strongly decreased the conformational dynamics mainly in the C-terminal domain of Ssz, whereas Zuotin acquired strong conformational stabilization in its N-terminal segment. Deletion of the highly flexible N terminus of Zuotin abolished stable association with Ssz in vitro and caused a phenotype resembling the loss of Ssz function in vivo. Thus, the C-terminal domain of Ssz, the N-terminal extension of Zuotin, and their mutual stabilization are the major structural determinants for RAC assembly. We furthermore found dynamic changes in the J-domain of Zuotin upon complex formation that might be crucial for RAC co-chaperone function. Taken together, we present a novel mechanism for converting Zuotin and Ssz chaperones into a functionally active dimer.