MAP3K1 functionally interacts with Axin1 in the canonical Wnt signalling pathway

S.S. Ng, T. Mahmoudi, V.S. Li, P. Hatzis, P.J. Boersema, S. Mohammed, A. Heck, H. Clevers

Research output: Contribution to journal/periodicalArticleScientificpeer-review


A central point of regulation in the Wnt/beta-catenin signalling pathway is the formation of the beta-catenin destruction complex. Axin1, an essential negative regulator of Wnt signalling, serves as a scaffold within this complex and is critical for rapid turnover of beta-catenin. To examine the mechanism by which Wnt signalling disables the destruction complex, we used an immunoprecipitation-coupled proteomics approach to identify novel endogenous binding partners of Axin1. We found mitogen-activated protein kinase kinase kinase 1 (MAP3K1) as an Axin1 interactor in Ls174T colorectal cancer (CRC) cells. Importantly, confirmation of this interaction in HEK293T cells indicated that the Axin1-MAP3K1 interaction is induced and modulated by Wnt stimulation. siRNA depletion of MAP3K1 specifically abrogated TCF/LEF-driven transcription and Wnt3A-driven endogenous gene expression in both HEK293T as well as DLD-1 CRC. Expression of ubiquitin ligase mutants of MAP3K1 abrogated TCF/LEF transcription, whereas kinase mutants had no effect in TCF-driven activity, highlighting the essential role of the MAP3K1 E3 ubiquitin ligase activity in regulation of the Wnt/beta-catenin pathway. These results suggest that MAP3K1, previously reported as an Axin1 inter-actor in c-Jun NH(2)-terminal kinase pathway, is also involved in the canonical Wnt signalling pathway and positively regulates expression of Wnt target genes.
Original languageEnglish
Pages (from-to)171-180
JournalBiological Chemistry
Issue number2-3
Publication statusPublished - 2010


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