| Literature DB >> 17512406 |
Thaddeus T Schug1, Daniel C Berry, Natacha S Shaw, Skylar N Travis, Noa Noy.
Abstract
Transcriptional activation of the nuclear receptor RAR by retinoic acid (RA) often leads to inhibition of cell growth. However, in some tissues, RA promotes cell survival and hyperplasia, activities that are unlikely to be mediated by RAR. Here, we show that, in addition to functioning through RAR, RA activates the "orphan" nuclear receptor PPARbeta/delta, which, in turn, induces the expression of prosurvival genes. Partitioning of RA between the two receptors is regulated by the intracellular lipid binding proteins CRABP-II and FABP5. These proteins specifically deliver RA from the cytosol to nuclear RAR and PPARbeta/delta, respectively, thereby selectively enhancing the transcriptional activity of their cognate receptors. Consequently, RA functions through RAR and is a proapoptotic agent in cells with high CRABP-II/FABP5 ratio, but it signals through PPARbeta/delta and promotes survival in cells that highly express FABP5. Opposing effects of RA on cell growth thus emanate from alternate activation of two different nuclear receptors.Entities:
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Year: 2007 PMID： 17512406 PMCID： PMC1948722 DOI： 10.1016/j.cell.2007.02.050
Source DB: PubMed Journal: Cell ISSN： 0092-8674 Impact factor: 41.582