Targeting of protein ubiquitination by BTB-Cullin 3-Roc1 ubiquitin ligases.
The concentrations and functions of many cellular proteins are regulated by the ubiquitin pathway. Cullin family proteins bind with the RING-finger protein Roc1 to recruit the ubiquitin-conjugating enzyme (E2) to the ubiquitin ligase complex (E3). Cul1 and Cul7, but not other cullins, bind to an adaptor protein, Skp1. Cul1 associates with one of many F-box proteins through Skp1 to assemble various SCF-Roc1 E3 ligases that each selectively ubiquitinate one or more specific substrates. Here, we show that Cul3, but not other cullins, binds directly to multiple BTB domains through a conserved amino-terminal domain. In vitro, Cul3 promoted ubiquitination of Caenorhabditis elegans MEI-1, a katanin-like protein whose degradation requires the function of both Cul3 and BTB protein MEL-26. We suggest that in vivo there exists a potentially large number of BCR3 (BTB-Cul3-Roc1) E3 ubiquitin ligases.
Furukawa
Manabu
M
Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, and Program in Molecular Biology and Biotechnology, University of North Carolina at Chapel Hill, NC 27599-7295, USA.
He
Yizhou Joseph
YJ
Borchers
Christoph
C
Xiong
Yue
Y
D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D025801:Ubiquitin / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases