학술논문
Structure and dynamics of a pentameric KCTD5/CUL3/Gβγ E3 ubiquitin ligase complex.
Document Type
Article
Author
Duc Minh Nguyen; Rath, Deanna H.; Devost, Dominic; Pétrin, Darlaine; Rizk, Robert; Ji, Alan X.; Narayanan, Naveen; Darren Yong; Yong, Darren; Kuntz, Douglas A.; Mian, Maha U. Q.; Pomroy, Neil C.; Keszei, Alexander F. A.; Benlekbir, Samir; Mazhab-Jafari, Mohammad T.; Rubinstein, John L.; Hébert, Terence E.; Privé, Gilbert G.
Source
Subject
*UBIQUITIN ligases
*PEPTIDES
*POST-translational modification
*G proteins
*NICKEL (Coin)
*UBIQUITINATION
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Language
ISSN
0027-8424
Abstract
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 (CRL3KCTD5) that ubiquitylates Gβγ and reduces Gβγ protein levels in cells. The cryo-EM structure of a 5:5:5 KCTD5/CUL3NTD/Gβ1γ2 assembly reveals a highly dynamic complex with rotations of over 60° between the KCTD5BTB/CUL3NTD and KCTD5CTD/Gβγ moieties of the structure. CRL3KCTD5 engages the E3 ligase ARIH1 to ubiquitylate Gβγ in an E3-E3 superassembly, and extension of the structure to include full-length CUL3 with RBX1 and an ARIH1~ubiquitin conjugate reveals that some conformational states position the ARIH1~ubiquitin thioester bond to within 10 Å of lysine-23 of Gβ 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/CUL3NTD/Gβγ 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. [ABSTRACT FROM AUTHOR]