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Updated: Aug 19, 2026

Immunofluorescence Analysis of Endogenous and Exogenous Centromere-kinetochore Proteins
Published on: March 3, 2016
The COP9 signalosome: an assembly and maintenance platform for cullin ubiquitin ligases?
Dieter A Wolf1, Chunshui Zhou, Susan Wee
1Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, MA 02115, USA. dwolf@hsph.harvard.edu
Abstract:
The COP9 signalosome (CSN) is a highly conserved protein complex implicated in diverse biological functions that involve ubiquitin-mediated proteolysis. Paradoxically, conserved enzymatic activities associated with CSN inhibit cullin ubiquitin ligase activity in vitro, whereas mutational analysis suggests that CSN promotes cullin-dependent proteolysis in vivo. This apparent paradox can be resolved in a model that proposes CSN-mediated cullin inhibition is a prerequisite for the proper assembly and maintenance of active cullin ubiquitin ligase complexes.
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