Cullin4B/E3-ubiquitin ligase negatively regulates [beta]-catenin

β-catenin is the key transducer of Wingless-type MMTV integration site family member (Wnt) signalling, upregulation of which is the cause of cancer of the colon and other tissues. In the absence of Wnt signals, β-catenin is targeted to ubiquitin-proteasome-mediated degradation. Here we present the f...

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Bibliographic Details
Published in:Journal of biosciences 2007-09, Vol.32, p.1133
Main Authors: Tripathi, Rachana, Kota, Satya Keerthi, Srinivas, Usha K
Format: Article
Language:English
Subjects:
Cellular biology
Enzymes
Genotype & phenotype
Insects
Mutation
Online Access:Get full text
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Summary:β-catenin is the key transducer of Wingless-type MMTV integration site family member (Wnt) signalling, upregulation of which is the cause of cancer of the colon and other tissues. In the absence of Wnt signals, β-catenin is targeted to ubiquitin-proteasome-mediated degradation. Here we present the functional characterization of E3-ubiquitin ligase encoded by cul4B. RNAi-mediated knock-down of Cul4B in a mouse cell line C3H T10 (1/2) results in an increase in β-catenin levels. Loss-of-function mutation in Drosophila cul4 also shows increased β-catenin/Armadillo levels in developing embryos and displays a characteristic naked-cuticle phenotype. Immunoprecipitation experiments suggest that Cul4B and β-catenin are part of a signal complex in Drosophila, mouse and human. These preliminary results suggest a conserved role for Cul4B in the regulation of β-catenin levels.[PUBLICATION ABSTRACT]
ISSN:0250-5991
0973-7138
DOI:10.1007/s12038-007-0114-0