pubmed:abstractText |
A number of G protein-coupled receptors have been shown to stimulate tuberin phosphorylation, which is critical for the regulation of translation and is apparently involved in neurotrophin-promoted survival of serum-deprived cells. Here, in HEK 293 cells transiently expressing the delta-, kappa-, or mu-opioid receptors, Western blotting analysis using a phosphospecific anti-tuberin antibody revealed a dose- and time-dependent increase in tuberin phosphorylation upon stimulation by specific opioid agonists. In NG108-15, PC12, and SH-SY5Y cells that endogenously express delta-, kappa-, and mu-opioid receptors, respectively, specific opioid agonists also stimulated tuberin phosphorylation in a dose- and time-dependent manner. Pretreatment of cells with pertussis toxin or PI3K inhibitor wortmannin blocked the opioid-stimulated tuberin phosphorylation, implicating the possible involvement of the G(i/o) proteins and the phosphatidylinositol-3 kinase/Akt pathway in opioid-induced tuberin phosphorylation. This is the first study that demonstrates the regulatory role of opioid receptors on tuberin.
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pubmed:affiliation |
Department of Biochemistry, The Molecular Neuroscience Center, The Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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