1. Arabidopsis ubiquitin-specific protease 6 (AtUBP6) interacts with calmodulin.
- Author
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Moon BC, Choi MS, Kang YH, Kim MC, Cheong MS, Park CY, Yoo JH, Koo SC, Lee SM, Lim CO, Cho MJ, and Chung WS
- Subjects
- Amino Acid Motifs, Amino Acid Sequence, Binding, Competitive, Calcium metabolism, Canavanine chemistry, Canavanine pharmacology, Dose-Response Relationship, Drug, Endopeptidases metabolism, Gene Library, Genetic Complementation Test, Glutathione Transferase metabolism, Horseradish Peroxidase metabolism, Humans, Models, Genetic, Molecular Sequence Data, Mutagenesis, Site-Directed, Mutation, Peptides chemistry, Phosphoric Diester Hydrolases metabolism, Protein Binding, Protein Structure, Tertiary, Sequence Homology, Amino Acid, Signal Transduction, Ubiquitin chemistry, Ubiquitin metabolism, Ubiquitin-Specific Proteases, Arabidopsis enzymology, Arabidopsis Proteins physiology, Calmodulin metabolism, Endopeptidases physiology
- Abstract
Calmodulin (CaM), a key Ca(2+) sensor in eukaryotes, regulates diverse cellular processes by interacting with many proteins. To identify Ca(2+)/CaM-mediated signaling components, we screened an Arabidopsis expression library with horseradish peroxidase-conjugated Arabidopsis calmodulin2 (AtCaM2) and isolated a homolog of the UBP6 deubiquitinating enzyme family (AtUBP6) containing a Ca(2+)-dependent CaM-binding domain (CaMBD). The CaM-binding activity of the AtUBP6 CaMBD was confirmed by CaM mobility shift assay, phosphodiesterase competition assay and site-directed mutagenesis. Furthermore, expression of AtUBP6 restored canavanine resistance to the Deltaubp6 yeast mutant. This is the first demonstration that Ca(2+) signaling via CaM is involved in ubiquitin-mediated protein degradation and/or stabilization in plants.
- Published
- 2005
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