National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
T32GM136614
米国
National Science Foundation (NSF, United States)
MCB-1714569
米国
National Science Foundation (NSF, United States)
DMR-1548924
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM128867
米国
National Institutes of Health/National Center for Research Resources (NIH/NCRR)
S10RR028893
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM145286
米国
Department of Energy (DOE, United States)
DE-FC02-02ER63421
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
T32GM145388
米国
引用
ジャーナル: bioRxiv / 年: 2025 タイトル: Structural basis for L-isoaspartyl-containing protein recognition by the PCMTD1 cullin-RING E3 ubiquitin ligase. 著者: Eric Z Pang / Boyu Zhao / Cameron Flowers / Elizabeth Oroudjeva / Jasmine B Winter / Vijaya Pandey / Michael R Sawaya / James Wohlschlegel / Joseph A Loo / Jose A Rodriguez / Steven G Clarke 要旨: A major type of spontaneous protein damage that accumulates with age is the formation of kinked polypeptide chains with L-isoaspartyl residues. Mitigating this damage is necessary for maintaining ...A major type of spontaneous protein damage that accumulates with age is the formation of kinked polypeptide chains with L-isoaspartyl residues. Mitigating this damage is necessary for maintaining proteome stability and prolonging organismal survival. While repair through methylation by PCMT1 has been previously shown to suppress L-isoaspartyl accumulation, we provide an additional mechanism for L-isoaspartyl maintenance through PCMTD1, a cullin-RING ligase (CRL). We combined cryo-EM, native mass spectrometry, and biochemical assays to provide insight on how the assembly and architecture of PCMTD1 in the context of a CRL complex fulfils this alternative mechanism. We show that the PCMTD1 CRL complex specifically binds L-isoaspartyl residues when bound to AdoMet. This work provides evidence for a growing class of E3 ubiquitin ligases that recognize spontaneous covalent modifications as potential substrates for ubiquitylation and subsequent proteasomal degradation. ETOC BLURB: Limiting the accrual of L-isoaspartyl damaged proteins is essential during aging. While this is thought to be mediated solely by the repair activity of the protein, PCMT1, Pang al. now ...ETOC BLURB: Limiting the accrual of L-isoaspartyl damaged proteins is essential during aging. While this is thought to be mediated solely by the repair activity of the protein, PCMT1, Pang al. now demonstrate that a related protein, PCMTD1, functions as a cullin-RING ligase to selectively target L-isoaspartyl-damaged substrates for potential regulation by the ubiquitylation-proteosomal system. HIGHLIGHTS: Atomic cryo-EM structure of CRL5-PCMTD1 determinedArchitecture of PCMTD1 when complexed as a CRL supports ubiquitylation activityPCMTD1 recognizes L-isoaspartyl residues as a recruitment ...HIGHLIGHTS: Atomic cryo-EM structure of CRL5-PCMTD1 determinedArchitecture of PCMTD1 when complexed as a CRL supports ubiquitylation activityPCMTD1 recognizes L-isoaspartyl residues as a recruitment motif for potential CRL activityRecognition of L-isoaspartyl residues is dependent on cofactor engagement.