Transforming growth factor beta suppresses beta-catenin/Wnt signaling and stimulates an adhesion response in human colon carcinoma cells in a Smad4/DPC4 independent manner.

Transforming growth factor beta (TGFbeta) suppresses the malignant phenotype of human colon carcinoma cells through diverse cellular pathways. Activation of beta-catenin/Wnt signal pathway underlies the malignant phenotype of human colon carcinomas. The Smad family of signal transducing, sequence-specific transcription activators are mediators of TGFbeta signaling.

Role of arginine-163 and the 163REEK166 motif in the oligomerization of truncated alpha A-crystallins.

To gain insight into the mechanism by which Arg-163 influences oligomerization of alphaA-crystallin, we prepared a series of truncated alphaA-crystallins with or without mutation of the Arg-163 residue. Expression of the proteins was achieved in Escherichia coli BL21 (DE3) pLysS cells, and alphaA-crystallin was purified by size-exclusion chromatography. Molecular mass was determined by molecular sieve HPLC, chaperone activity was assayed with alcohol dehydrogenase as the target protein, and structural changes were ascertained by circular dichroism (CD) measurements.

Effect of oxidation of alphaA- and alphaB-crystallins on their structure, oligomerization and chaperone function.

The purpose of this study was to investigate the effect of metal-catalyzed oxidation by H(2)O(2) on the structure, oligomerization, and chaperone function of alphaA- and alphaB-crystallins. Recombinant alphaA-and alphaB-crystallins were prepared by expressing them in E. coli and purifying by size-exclusion chromatography.