Rajnish Gupta

Publication Details

  • Peroxisome proliferator-activated receptor gamma and transforming growth factor-beta pathways inhibit intestinal epithelial cell growth by regulating levels of TSC-22 JOURNAL OF BIOLOGICAL CHEMISTRY Gupta, R. A., Sarraf, P., Brockman, J. A., Shappell, S. B., Raftery, L. A., Willson, T. M., DuBois, R. N. 2003; 278 (9): 7431-7438


    Peroxisome proliferator-activated receptor gamma (PPARgamma) and transforming growth factor-beta (TGF-beta) are key regulators of epithelial cell biology. However, the molecular mechanisms by which either pathway induces growth inhibition and differentiation are incompletely understood. We have identified transforming growth factor-simulated clone-22 (TSC-22) as a target gene of both pathways in intestinal epithelial cells. TSC-22 is member of a family of leucine zipper containing transcription factors with repressor activity. Although little is known regarding its function in mammals, the Drosophila homolog of TSC-22, bunched, plays an essential role in fly development. The ability of PPARgamma to induce TSC-22 was not dependent on an intact TGF-beta1 signaling pathway and was specific for the gamma isoform. Localization studies revealed that TSC-22 mRNA is enriched in the postmitotic epithelial compartment of the normal human colon. Cells transfected with wild-type TSC-22 exhibited reduced growth rates and increased levels of p21 compared with vector-transfected cells. Furthermore, transfection with a dominant negative TSC-22 in which both repressor domains were deleted was able to reverse the p21 induction and growth inhibition caused by activation of either the PPARgamma or TGF-beta pathways. These results place TSC-22 as an important downstream component of PPARgamma and TGF-beta signaling during intestinal epithelial cell differentiation.

    View details for DOI 10.1074/jbc.M208076200

    View details for Web of Science ID 000181195100103

    View details for PubMedID 12468551

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