%0 Journal Article
%T Mechanism of Ψ-Pro/C-degron recognition by the CRL2FEM1B ubiquitin ligase.
%A Chen X
%A Raiff A
%A Li S
%A Guo Q
%A Zhang J
%A Zhou H
%A Timms RT
%A Yao X
%A Elledge SJ
%A Koren I
%A Zhang K
%A Xu C
%J Nat Commun
%V 15
%N 1
%D 2024 Apr 26
%M 38670995
%F 17.694
%R 10.1038/s41467-024-47890-5
%X The E3 ligase-degron interaction determines the specificity of the ubiquitin‒proteasome system. We recently discovered that FEM1B, a substrate receptor of Cullin 2-RING ligase (CRL2), recognizes C-degrons containing a C-terminal proline. By solving several cryo-EM structures of CRL2FEM1B bound to different C-degrons, we elucidate the dimeric assembly of the complex. Furthermore, we reveal distinct dimerization states of unmodified and neddylated CRL2FEM1B to uncover the NEDD8-mediated activation mechanism of CRL2FEM1B. Our research also indicates that, FEM1B utilizes a bipartite mechanism to recognize both the C-terminal proline and an upstream aromatic residue within the substrate. These structural findings, complemented by in vitro ubiquitination and in vivo cell-based assays, demonstrate that CRL2FEM1B-mediated polyubiquitination and subsequent protein turnover depend on both FEM1B-degron interactions and the dimerization state of the E3 ligase complex. Overall, this study deepens our molecular understanding of how Cullin-RING E3 ligase substrate selection mediates protein turnover.