Structure and dynamics of a pentameric KCTD5/CUL3/Gβγ E3 ubiquitin ligase complex

• 成果类型: Article
• 署名作者: Nguyen, Duc Minh; Rath, Deanna H.; Devost, Dominic; Petrin, Darlaine; Rizk, Robert; Ji, Alan X.; Narayanan, Naveen; Yong, Darren; Zhai, Andrew; Kuntz, Douglas A.; Mian, Maha U. Q.; Pomroy, Neil C.; Keszei, Alexander F. A.; Benlekbir, Samir; Mazhab-Jafari, Mohammad T.; Rubinstein, John L.; Hebert, Terence E.; Prive, Gilbert G.
• 署名单位: University of Toronto; University Health Network Toronto; Princess Margaret Cancer Centre; University of Toronto; McGill University; University of Toronto; Hospital for Sick Children (SickKids); University of Toronto
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14441
• DOI: 10.1073/pnas.2315018121
• 发表日期: 2024-04-23
• 关键词: beta-gamma-subunits; cryo-em; insights; kctd; proteins; FAMILY; RECOGNITION; refinement; cullin3; SYSTEM

摘要

Heterotrimeric G proteins can be regulated by posttranslational modifications, including ubiquitylation. KCTD5, a pentameric substrate receptor protein consisting of an N-terminal BTB domain and a C-terminal domain, engages CUL3 to form the central scaffold of a cullin-RING E3 ligase complex (CRL3(KCTD5)) that ubiquitylates G beta gamma and reduces G beta gamma protein levels in cells. The cryo-EM structure of a 5:5:5 KCTD5/CUL3(NTD)/G beta(1)gamma(2) assembly reveals a highly dynamic complex with rotations of over 60 degrees between the KCTD5 BTB /CUL3(NTD) and KCTD5(CTD)/G beta gamma moieties of the structure. CRL3(KCTD5) engages the E3 ligase ARIH1 to ubiquitylate G beta gamma in an E3-E3 superassembly, and extension of the structure to include full-length CUL3 with RBX1 and an ARIH1 similar to ubiquitin conjugate reveals that some conformational states position the ARIH1 similar to ubiquitin thioester bond to within 10 angstrom of lysine-23 of G beta and likely represent priming complexes. Most previously described CRL/substrate structures have consisted of monovalent complexes and have involved flexible peptide substrates. The structure of the KCTD5/CUL3(NTD)/G beta gamma complex shows that the oligomerization of a substrate receptor can generate a polyvalent E3 ligase complex and that the internal dynamics of the substrate receptor can position a structured target for ubiquitylation in a CRL3 complex.