The COP9 Signalosome Variant CSNCSN7A Stabilizes the Deubiquitylating Enzyme CYLD Impeding Hepatic Steatosis

The COP9 signalosome

But what does it really do? This is the $64,000 question. If we must join in the rampant speculation, the CSN probably has multiple functions. It may serve as a master dock, bringing together proteins, such as a kinase, its substrate, and the proteasome. The CSN might even be an alternative or additional proteasome lid, shuttling ubiquitinated substrates from the SCF to the proteasome. Alternat...

The COP9 signalosome.

The COP9 signalosome (CSN) is composed of eight distinct subunits and is highly homologous to the lid sub-complex of the 26S proteasome. CSN was initially defined as a repressor of photomorphogenesis in Arabidopsis, and it has now been found to participate in diverse cellular and developmental processes in various eukaryotic organisms. Recently, CSN was revealed to have a metalloprotease activi...

JAB1/CSN5 and the COP9 signalosome

The Jun activating binding protein (JAB1) specifically stabilizes complexes of c-Jun or JunD with AP-1 sites, increasing the specificity of target gene activation by AP-1 proteins. JAB1 is also known as COP9 signalosome subunit 5 (CSN5), which is a component of the COP9 signalosome regulatory complex (CSN). Over the past year, JAB1/CSN5 has been implicated in numerous signaling pathways includi...

A systems approach to the COP9 signalosome.

Retinoblastoma protein regulation by the COP9 signalosome.

Similar to their human counterparts, the Drosophila Rbf1 and Rbf2 Retinoblastoma family members control cell cycle and developmentally regulated gene expression. Increasing evidence suggests that Rbf proteins rely on multiprotein complexes to control target gene transcription. We show here that the developmentally regulated COP9 signalosome (CSN) physically interacts with Rbf2 during embryogene...