β-catenin has a dual function; it is implicated in intercellular junctions and transcriptional co-activation. Here we examined the regulation of the expression and localization of β-catenin in HT29 colorectal adenocarcinoma cells. Our results showed that inhibition of PI-3 kinase with wortmannin was accompanied by a considerably reduced expression of β-catenin. This effect was overcome by butyrate and occured at the protein level, not at the level of mRNA. Moreover, NaBT significantly increased the phosphorylation of the ribosomal protein, S6, known to participate in the translational control of gene expression. This was accompanied by the increased phosphorylation of p70 S6K and MAPKs, the effector proteins that are upstream of protein S6 in the distinct signaling pathways. These facts indicate that different signaling pathways may be involved in the regulation of β-catenin synthesis. Modulation of β-catenin expression induced by NaBT appeared to occur at the level of protein translation, suggesting that NaBT may act as a translational regulator.

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