Hsp70 Chaperones

Abstract

Originally published in: Protein Folding Handbook. Part II. Edited by Johannes Buchner and Thomas Kiefhaber. Copyright © 2005 Wiley‐VCH Verlag GmbH & Co. KGaA Weinheim. Print ISBN: 3‐527‐30784‐2 The sections in this article are Introduction “Soluble” Hsp 70 s / J ‐proteins Function in General Protein Folding The Soluble Hsp 70 of E . coli , Dna K Soluble Hsp 70 s of Major Eukaryotic Cellular Compartments Eukaryotic Cytosol Matrix of Mitochondria Lumen of the Endoplasmic Reticulum “Tethered” Hsp 70 s / J ‐proteins: Roles in Protein Folding on the Ribosome and in Protein Translocation Membrane‐tethered Hsp 70/ J ‐protein Ribosome‐associated Hsp 70/ J ‐proteins Modulating of Protein Conformation by Hsp 70 s / J ‐proteins Assembly of Fe / S Centers Uncoating of Clathrin‐coated Vesicles Regulation of the Heat Shock Response Regulation of Activity of DNA Replication‐initiator Proteins Cases of a Single Hsp 70 Functioning With Multiple J ‐Proteins Hsp 70 s / J ‐proteins – When an Hsp 70 Maybe Isn't Really a Chaperone The Ribosome‐associated “ Hsp 70” Ssz 1 Mitochondrial Hsp 70 as the Regulatory Subunit of an Endonuclease Conclusions

The mitochondrial Hsp70 chaperone Ssq1 facilitates Fe/S cluster transfer from Isu1 to Grx5 by complex formation

“…Client proteins interacting with the peptide-binding domain of Hsp70 chaperones stimulate their ATPase activity (Mayer and Bukau, 2005; Craig and Marszalek, 2011). The increased ATPase activity of Hsp70 is considered to be a hallmark of productive interaction with partner proteins.…”

“…, 2003; Silberg et al. , 2004; Vickery and Cupp-Vickery, 2007; Craig and Marszalek, 2011). In the bacterial ISC system, the conformational change of the U-type scaffold protein induced upon binding to the Ssq1 orthologue HscA induces the weakening of Fe/S cluster association to IscU (Bonomi et al.…”

“…Unraveling of this Hsp70 cycle has largely benefited from numerous studies on the role of these chaperones in protein folding (Bukau and Horwich, 1998; Mayer and Bukau, 2005; Craig and Marszalek, 2011; Hartl et al. , 2011; Schlecht et al.…”

“…, 2002; Muhlenhoff et al. , 2003; Vickery and Cupp-Vickery, 2007; Kampinga and Craig, 2010; Craig and Marszalek, 2011). Most eukaryotes use the multifunctional Hsp70 of the mitochondrial matrix together with the specialized cochaperone Jac1, which specifically recruits Hsp70 for Fe/S protein maturation (Schilke et al.…”

Iron–Sulfur Cluster Biogenesis Chaperones: Evidence for Emergence of Mutational Robustness of a Highly Specific Protein–Protein Interaction

“…Protein machineries specializing in facilitating cluster assembly on and cluster transfer from a scaffold protein are present in all domains of life. In most proteobacteria and mitochondria of eukaryotes, an Hsp70 molecular chaperone and J-protein cochaperone partner play a critical role in the transfer of clusters to recipient apoproteins (Vickery and Cupp-Vickery 2007;Craig and Marszalek 2011). Although most of the mitochondrial proteins involved in FeS biogenesis were inherited from bacterial ancestors, the evolutionary history of Hsp70 functioning in this process is rather complex (Schilke et al 2006;Pukszta et al 2010).…”