Hsp70 Interacts with the Retroviral Restriction Factor TRIM5α and Assists the Folding of TRIM5α

• Type of Material: Article
• Authors: Chae Young Hwang, Emory University; Jens Holl, Emory University; Devi Rajan, Emory University; Younglang Lee, Emory University; Susan Kim, Emory University; Moonkyoung Um, Boston Biomedical Research Institute; Ki-Sun Kwon, Korea Research Institute of Bioscience and Biotechnology; Byeongwoon Song, Emory University
• Language: English
• Date: 2010-03-05
• Publisher: American Society for Biochemistry and Molecular Biology
• Publication Version: Final Published Version
• Copyright Statement: © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.
• Final Published Version (URL): http://www.jbc.org/content/285/10/7827
• Title of Journal or Parent Work: Journal of Biological Chemistry
• ISSN: 0021-9258
• Volume: 285
• Issue: 10
• Start Page: 7827
• End Page: 7837
• Grant/Funding Information: This work was supported by the Campbell Foundation Award, Emory University Research Committee Award, Emory Egleston Children's Research Center Award, and Emory Center for AIDS Research Award P30AI050409 (to B. S.), and partially supported by the Korea Research Council of Fundamental Science and Technology Award M10642040003 and National Research Foundation of Korea Award M10503010002 (to K.-S. K.).
• Keywords: ER Stress; Protein Folding; Ubiquitination; E3 Ubiquitin Ligase; Hsp70; HIV; TRIM; Apoptosis; Chaperone
• Research Categories: Biology, Cell; Chemistry, Biochemistry; Health Sciences, General

Abstract

Tripartite motif (TRIM) protein TRIM5α has been shown to restrict human immunodeficiency virus, type 1 infection in Old World monkey cells at the early post-entry step by poorly understood mechanisms. Currently, the physiological function of TRIM5α is not known. In this study, we showed that transiently overexpressed TRIM5α causes a morphological change in HEK293T cells. A proteomics analysis of the protein complexes that were pulled down with hemagglutinin-tagged TRIM5α suggested that the heat shock protein 70 (Hsp70) may serve as a TRIM5α-binding partner. The interaction between Hsp70 and TRIM5α was confirmed by co-localization and co-immunoprecipitation assays. Co-expression of Hsp70 reversed the TRIM5α-induced morphological change in HEK293T cells. Another heat shock protein Hsc70 also bound to TRIM5α, but unlike Hsp70, Hsc70 was not able to reverse the TRIM5α-induced morphological change, suggesting that Hsp70 specifically reverses the morphological change caused by TRIM5α. Studies using a series of TRIM5α deletion mutants demonstrate that, although the PRYSPRY domain is critical for binding to Hsp70, the entire TRIM5α structure is necessary to induce the morphological change of cells. When the ATPase domain of Hsp70 was mutated, the mutated Hsp70 could not counteract the morphological change induced by TRIM5α, indicating that the catalytic activity of Hsp70 protein is important for this function. Co-expression of Hsp70 elevated the levels of TRIM5α in the detergent-soluble fraction with a concomitant decrease in the detergent-insoluble fraction. Together these results suggest that Hsp70 plays critical roles in the cellular management against the TRIM5α-induced cellular insults.