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- Title
IP6-assisted CSN-COP1 competition regulates a CRL4-ETV5 proteolytic checkpoint to safeguard glucose-induced insulin secretion.
- Authors
Lin, Hong; Yan, Yuan; Luo, Yifan; So, Wing Yan; Wei, Xiayun; Zhang, Xiaozhe; Yang, Xiaoli; Zhang, Jun; Su, Yang; Yang, Xiuyan; Zhang, Bobo; Zhang, Kangjun; Jiang, Nan; Chow, Billy Kwok Chong; Han, Weiping; Wang, Fengchao; Rao, Feng
- Abstract
COP1 and COP9 signalosome (CSN) are the substrate receptor and deneddylase of CRL4 E3 ligase, respectively. How they functionally interact remains unclear. Here, we uncover COP1–CSN antagonism during glucose-induced insulin secretion. Heterozygous Csn2WT/K70E mice with partially disrupted binding of IP6, a CSN cofactor, display congenital hyperinsulinism and insulin resistance. This is due to increased Cul4 neddylation, CRL4COP1 E3 assembly, and ubiquitylation of ETV5, an obesity-associated transcriptional suppressor of insulin secretion. Hyperglycemia reciprocally regulates CRL4-CSN versus CRL4COP1 assembly to promote ETV5 degradation. Excessive ETV5 degradation is a hallmark of Csn2WT/K70E, high-fat diet-treated, and ob/ob mice. The CRL neddylation inhibitor Pevonedistat/MLN4924 stabilizes ETV5 and remediates the hyperinsulinemia and obesity/diabetes phenotypes of these mice. These observations were extended to human islets and EndoC-βH1 cells. Thus, a CRL4COP1-ETV5 proteolytic checkpoint licensing GSIS is safeguarded by IP6-assisted CSN-COP1 competition. Deregulation of the IP6-CSN-CRL4COP1-ETV5 axis underlies hyperinsulinemia and can be intervened to reduce obesity and diabetic risk. Mediators of insulin signalling are targets of cullin-RING ubiquitin ligases (CRL) that mediate protein degradation, but the role of protein degradation in insulin signalling is incompletely understood. Here, the authors identified a glucose-responsive CRL4-COP1-ETV5 proteolytic axis that promotes insulin secretion, and is inhibited under hypoglycemia.
- Subjects
INSULIN; SECRETION; UBIQUITIN ligases; PROTEOLYSIS; HYPERINSULINISM
- Publication
Nature Communications, 2021, Vol 12, Issue 1, p1
- ISSN
2041-1723
- Publication type
Article
- DOI
10.1038/s41467-021-22941-3