A role of Arabidopsis COP9 signalosome in multifaceted developmental processes revealed by the characterization of its subunit 3.
The COP9 signalosome is a highly conserved eight-subunit protein complex initially defined as a repressor of photomorphogenic development in Arabidopsis. It has recently been suggested that the COP9 signalosome directly interacts and regulates SCF type E3 ligases, implying a key role in ubiquitin-proteasome mediated protein degradation. We report that Arabidopsis FUS11 gene encodes the subunit 3 of the COP9 signalosome (CSN3). The fus11 mutant is defective in the COP9 signalosome and accumulates significant amount of multi-ubiquitinated proteins. The same mutant is specifically impaired in the 26S proteasome-mediated degradation of HY5 but not PHYA, indicating a selective involvement in protein degradation. Reduction-of-function transgenic lines of CSN3 produced through gene co-suppression also accumulate multi-ubiquitinated proteins and exhibit diverse developmental defects. This result substantiates a hypothesis that the COP9 signalosome is involved in multifaceted developmental processes through regulating proteasome-mediated protein degradation.
Peng
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Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA.
Serino
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Deng
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XW
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins; D001483:Base Sequence; D000075686:COP9 Signalosome Complex; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D009154:Mutation; D009687:Nuclear Proteins; D010447:Peptide Hydrolases; D018515:Plant Leaves / Q000254:growth & development; D010940:Plant Proteins / Q000378:metabolism; D018514:Plant Structures / Q000235:genetics / Q000254:growth & development; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D025801:Ubiquitin / Q000378:metabolism
D029681:Arabidopsis Proteins; C000618792:FUS11 protein, Arabidopsis; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D010940:Plant Proteins; D011506:Proteins; D025801:Ubiquitin; D011494:Protein Kinases; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex