A conserved regulatory complex (constitutive photomorphogenic-9 complex) present in diverse organisms. The complex has eight subunits (CSN1–8; total 450 kDa) with some homologies to the proteosome. Subunits include Gps1, Jab1 (a coactivator of AP-1 transcription factor), CSN5 (a isopeptidase and a candidate oncogene in human breast cancer), TRIP15 (thyroid hormone receptor interactor-15), SGN3 (which has homology to the 26S proteosome S3 regulatory subunit), and others. Remarkably, human Gps1 can substitute for FUS6 (the plant homologue) in the COP9 complex that represses photomorphogenesis in Arabidopsis thaliana. Inactivation of the COP9 signalosome will impair T-cell development.
Subjects: Medicine and Health.