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.
Mesh Terms:
Amino Acid Sequence, Arabidopsis, Base Sequence, Chromosome Mapping, Cloning, Molecular, Gene Expression Regulation, Plant, Molecular Sequence Data, Multiprotein Complexes, Mutation, Nuclear Proteins, Peptide Hydrolases, Plant Leaves, Plant Proteins, Plant Structures, Protein Kinases, Proteins, Sequence Homology, Amino Acid, Substrate Specificity, Ubiquitin
Development
Date: Nov. 01, 2001
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