Arabidopsis ubiquitin-specific protease 6 (AtUBP6) interacts with calmodulin

• Published in: FEBS letters 2005-07, Vol.579 (18), p.3885-3890
• Main Authors: Moon, Byeong Cheol, Choi, Man Soo, Kang, Yun Hwan, Kim, Min Chul, Cheong, Mi Sun, Park, Chan Young, Yoo, Jae Hyuk, Koo, Sung Cheol, Lee, Sang Min, Lim, Chae Oh, Cho, Moo Je, Chung, Woo Sik
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs; Amino Acid Sequence; Arabidopsis; Arabidopsis - enzymology; Arabidopsis calmodulin2; Arabidopsis Proteins - physiology; AtCaM2; Binding, Competitive; Calcium - metabolism; Calmodulin; Calmodulin - metabolism; Calmodulin-binding protein; CaM; CaM-binding domain; CaM-binding protein; CaMBD; CaMBP; Canavanine - chemistry; Canavanine - pharmacology; Deubiquitination; deubiquitination enzyme; Dose-Response Relationship, Drug; DUB; Endopeptidases - metabolism; Endopeptidases - physiology; Gene Library; Genetic Complementation Test; glutathione S-transferase; Glutathione Transferase - metabolism; GST; horseradish peroxidase; Horseradish Peroxidase - metabolism; HRP; Humans; Models, Genetic; Molecular Sequence Data; Mutagenesis, Site-Directed; Mutation; PDE; Peptides - chemistry; phosphodiesterase; Phosphoric Diester Hydrolases - metabolism; Protein Binding; Protein Structure, Tertiary; Sequence Homology, Amino Acid; Signal Transduction; ubiquitin; Ubiquitin - chemistry; Ubiquitin - metabolism; Ubiquitin-specific protease; Ubiquitin-Specific Proteases; Ubiquitin–proteasome pathway; UBP
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2005.05.080

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 Δ ubp6 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.