Samenvatting
β-catenin mediates Wnt signaling by acting as the essential co-activator for TCF transcription factors. Wnt signaling increases the half-life and therefore the absolute level of β-catenin in responding cells. The current model states that these changes in β-catenin stability set the threshold for Wnt signaling. However, we find that pharmacological inhibition of proteasome activity by ALLN leads to accumulation of cytosolic β-catenin but not to increased TCF-mediated transcription. In addition, in temperature-sensitive ubiquitylation mutant CHO cells inhibition of ubiquitylation increases β-catenin levels, but does not induce transcriptional activation of TCF reporter genes. Using an antibody specific for β-catenin dephosphorylated at residues Ser37 and Thr41, we show that Wnt signals specifically increase the levels of dephosphorylated β-catenin, whereas ALLN does not. We conclude that changes in the phosphorylation status of the N-terminus of β-catenin that occur upon Wnt signaling independently affect the signaling properties and half-life of β-catenin. Hence, Wnt signals are transduced via N-terminally dephosphorylated β-catenin.
Originele taal-2 | Engels |
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Pagina's (van-tot) | 63-68 |
Aantal pagina's | 6 |
Tijdschrift | EMBO Reports |
Volume | 3 |
Nummer van het tijdschrift | 1 |
DOI's | |
Status | Gepubliceerd - 2002 |
Extern gepubliceerd | Ja |