Serine phosphorylation facilitates protein degradation by the human mitochondrial ClpXP protease

• 成果类型: Article
• 署名作者: Feng, Yue; Goncalves, Monica M.; Jitkova, Yulia; Keszei, Alexander F. A.; Yan, Yongran; Sarathy, Chaitra; St-Germain, Jonathan; Kenney, Tristan M. G.; Tcheng, Matthew; Trudel, Vincent; Mancini, Ross S.; Upadhyay, Rahul; Hurren, Rose; Gronda, Marcela; Schultz, Matthew; Soriano, Kaylen; Lees, Kaitlin; Pomroy, Neil C.; Currie, S. Quinn W.; Prive, Gilbert G.; Reed, Mark A.; Yudin, Andrei K.; Penn, Linda Z.; Arrowsmith, Cheryl H.; Raught, Brian; Mazhab-jafari, Mohammad T.; Vahidi, Siavash; Schimmer, Aaron D.
• 署名单位: University of Toronto; University Health Network Toronto; Princess Margaret Cancer Centre; University of Toronto; University of Guelph; University of Toronto; Krembil Research Institute; University of Toronto; University Health Network Toronto; University of Toronto; University of Toronto; Structural Genomics Consortium
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14333
• DOI: 10.1073/pnas.2422447122
• 发表日期: 2025-02-04
• 关键词: hydrogen/deuterium exchange; tau phosphorylation; mass-spectrometry; inhibitors; RECOGNITION; proteolysis; complex; SYSTEM; potent; roles

摘要

ClpXP is a two- component mitochondrial matrix protease. The caseinolytic mitochondrial matrix peptidase chaperone subunit X (ClpX) recognizes and translocates protein substrates into the degradation chamber of the caseinolytic protease P (ClpP) for proteolysis. ClpXP degrades damaged respiratory chain proteins and is necessary for cancer cell survival. Despite the critical role of ClpXP in mitochondrial protein quality control, the specific degrons, or modifications that tag substrate proteins for degradation by human ClpXP, are still unknown. We demonstrated that phosphorylated serine (pSer) targets substrates to ClpX and facilitates their degradation by ClpXP in biochemical assays. In contrast, ClpP hyperactivated by the small- molecule drug ONC201 lost the preference bined with biochemical assays showed that pSer binds the RKL loop of ClpX. ClpX variants with substitutions in the RKL loop failed to recognize phosphorylated substrates. In intact cells, ClpXP also preferentially degraded substrates with pSer. Moreover, ClpX substrates with the pSer were selectively found in aggregated mitochondrial proteins. Our work uncovers a mechanism for substrate recognition by ClpXP, with implications for targeting acute myeloid leukemia and other disorders involving ClpXP dysfunction.