CSNAP, the smallest CSN subunit, modulates proteostasis through cullin-RING ubiquitin ligases

Maria G. Fuzesi-Levi, Irit Fainer, Radoslav Ivanov Enchev, Gili Ben-Nissan, Yishai Levin, Meital Kupervaser, Tomer Meir Salame, Reinat Nevo, Matthias Peter, Michal Sharon

Research output: Contribution to journalArticlepeer-review

Abstract

The cullin-RING ubiquitin E3 ligase (CRL) family consists of similar to 250 complexes that catalyze ubiquitylation of proteins to achieve cellular regulation. All CRLs are inhibited by the COP9 signalosome complex (CSN) through both enzymatic (deneddylation) and nonenzymatic (steric) mechanisms. The relative contribution of these two mechanisms is unclear. Here, we decouple the mechanisms using CSNAP, the recently discovered ninth subunit of the CSN. We find that CSNAP reduces the affinity of CSN toward CRL complexes. Removing CSNAP does not affect deneddylation, but leads to global effects on the CRL, causing altered reproductive capacity, suppressed DNA damage response, and delayed cell cycle progression. Thus, although CSNAP is only 2% of the CSN mass, it plays a critical role in the steric regulation of CRLs by the CSN.

Original languageEnglish
Pages (from-to)984-998
Number of pages15
JournalCell Death and Differentiation
Volume27
Issue number3
Early online date31 Jul 2019
DOIs
StatePublished - Mar 2020

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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