Structural highlights
Function
ZUO1_YEAST Component of the ribosome-associated complex (RAC), a heterodimeric chaperone complex involved in regulation of accurate translation termination and in folding or maintaining nascent polypeptides in a folding-competent state. RAC stimulates the ATPase activity of the ribosome-associated pool of Hsp70-type chaperones SSB1/SSB2 that bind to the nascent polypeptide chain. ZUO1 can act as a J-protein for SSB1/SSB2 only when associated with SSZ1.[1] [2]
Publication Abstract from PubMed
Ribosome-associated J protein-Hsp70 chaperones promote nascent-polypeptide folding and normal translational fidelity. The J protein Zuo1 is known to span the ribosomal subunits, but understanding of its function is limited. Here we present new structural and cross-linking data allowing more precise positioning of Saccharomyces cerevisiae Zuo1 near the 60S polypeptide-exit site and suggesting interactions of Zuo1 with the ribosomal protein eL31 and 25S rRNA helix 24. The junction between the 60S-interacting and subunit-spanning helices is a hinge that positions Zuo1 on the 40S yet accommodates subunit rotation. Interaction between the Zuo1 C terminus and 40S occurs via 18S rRNA expansion segment 12 (ES12) of helix 44, which originates at the decoding site. Deletions in either ES12 or the Zuo1 C terminus alter readthrough of stop codons and -1 frameshifting. Our study offers insight into how this cotranslational chaperone system may monitor decoding-site activity and nascent-polypeptide transit, thereby coordinating protein translation and folding.
Dual interaction of the Hsp70 J-protein cochaperone Zuotin with the 40S and 60S ribosomal subunits.,Lee K, Sharma R, Shrestha OK, Bingman CA, Craig EA Nat Struct Mol Biol. 2016 Sep 26. doi: 10.1038/nsmb.3299. PMID:27669034[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Rakwalska M, Rospert S. The ribosome-bound chaperones RAC and Ssb1/2p are required for accurate translation in Saccharomyces cerevisiae. Mol Cell Biol. 2004 Oct;24(20):9186-97. PMID:15456889 doi:http://dx.doi.org/10.1128/MCB.24.20.9186-9197.2004
- ↑ Huang P, Gautschi M, Walter W, Rospert S, Craig EA. The Hsp70 Ssz1 modulates the function of the ribosome-associated J-protein Zuo1. Nat Struct Mol Biol. 2005 Jun;12(6):497-504. Epub 2005 May 22. PMID:15908962 doi:http://dx.doi.org/10.1038/nsmb942
- ↑ Lee K, Sharma R, Shrestha OK, Bingman CA, Craig EA. Dual interaction of the Hsp70 J-protein cochaperone Zuotin with the 40S and 60S ribosomal subunits. Nat Struct Mol Biol. 2016 Sep 26. doi: 10.1038/nsmb.3299. PMID:27669034 doi:http://dx.doi.org/10.1038/nsmb.3299
