Open AccessCOP9 signalosome subunits protect Capicua from MAP kinase-dependent and independent mechanisms of degradation
Author(s) -
Annabelle Suisse,
Danqing He,
Kevin Legent,
Jessica E. Treisman
Publication year - 2017
Publication title -
development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.15
H-Index - 36
eISSN - 1477-9129
pISSN - 0950-1991
DOI - 10.1242/dev.148767
Subject(s) - cop9 signalosome , cullin , biology , ubiquitin ligase , ubiquitin , skp1 , microbiology and biotechnology , nedd8 , protein subunit , gene , genetics , biochemistry , protease , peptide hydrolases , enzyme
The COP9 signalosome removes Nedd8 modifications from the Cullin subunits of ubiquitin ligase complexes, reducing their activity. Here we show that mutations in the Drosophila COP9 signalosome subunit 1b (CSN1b) gene increase the activity of ubiquitin ligases that contain Cullin 1. Analysis of CSN1b mutant phenotypes revealed a requirement for the COP9 signalosome to prevent ectopic expression of Epidermal growth factor receptor (EGFR) target genes. It does so by protecting Capicua, a transcriptional repressor of EGFR target genes, from EGFR pathway-dependent ubiquitination by a Cullin 1/SKP1-related A/Archipelago E3 ligase and subsequent proteasomal degradation. The CSN1b subunit also maintains basal Capicua levels by protecting it from a separate mechanism of degradation that is independent of EGFR signaling. As a suppressor of tumor growth and metastasis, Capicua may be an important target of the COP9 signalosome in cancer.