The COP/DET/FUS proteins-regulators of eukaryotic growth and development.
Eleven recessive mutant loci define the class of cop / det / fus mutants of Arabidopsis. The cop / det / fus mutants mimic the phenotype of light-grown seedlings when grown in the dark. At least four cop / det / fus mutants carry mutations in subunits of the COP9 signalosome, a multiprotein complex paralogous to the 'lid' subcomplex of the 26S proteasome. COP1, another COP/DET/FUS protein, is itself not a subunit of the COP9 signalosome. In the dark, COP1 accumulates in the nucleus where it is required for the degradation of the HY5 protein, a positive regulator of photomorphogenesis. In the light, COP1 is excluded from the nucleus and the constitutively nuclear HY5 protein can accumulate. Nuclear accumulation of COP1 and degradation of HY5 are impaired in the cop / det / fus mutants that carry mutations in subunits of the COP9 signalosome. Although the cellular function of the COP/DET/FUS proteins is not yet well understood, taken together the current findings suggest that the COP/DET/FUS proteins repress photomorphogenesis in the dark by mediating specific protein degradation.
Schwechheimer
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Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA.
Deng
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D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins; D000075686:COP9 Signalosome Complex; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D003624:Darkness; D047908:Intracellular Signaling Peptides and Proteins; D009024:Morphogenesis; D046912:Multiprotein Complexes; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010447:Peptide Hydrolases; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C088435:DET1 protein, Arabidopsis; D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D010940:Plant Proteins; D021122:Protein Subunits; D011506:Proteins; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex