Regulation of the stress-like protein adenotin in PC 12 cells by ethanol exposure.
The effects of chronic ethanol exposure on the stress-like protein adenotin were investigated using the radioligand [3H]-5'-N-ethylcarboxamidoadenosine ([3H]NECA). A 4-day exposure to 150 mM ethanol increased both the KD and the density of [3H]NECA binding sites. These changes were not due to residual ethanol as the acute addition of ethanol did not alter [3H]NECA binding. Chronic ethanol exposure of A126-1B2-1 cells, which are a mutant PC 12 cell line deficient in protein kinase A (PKA), increased the cellular density of adenotin, but did not affect the KD for the radioligand. Conversely, when PC 12 cells were exposed to 10 microM forskolin for either 2 or 4 days, the cellular density of adenotin was not altered, but the affinity of adenotin for [3H]NECA was reduced significantly. An increase in KD was not observed after a 1-hr exposure of PC 12 cells to forskolin, indicating that the reduction in affinity for the radioligand was not due simply to a PKA-mediated phosphorylation of adenotin. The present study demonstrated that chronic ethanol regulates adenotin through two different mechanisms. The ethanol-induced increase in the density of adenotin does not involve PKA, while the reduction in affinity ap pears to involve a cAMP-dependent mechanism.
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Department of Pharmacology and Toxicology, Suny at Buffalo, NY 14214-3000, USA.
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000096:biosynthesis*; D000242:Cyclic AMP / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D008565:Membrane Proteins / Q000096:biosynthesis*; D016716:PC12 Cells; D051381:Rats
D002352:Carrier Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; C064982:adenotin; D019830:Adenosine-5'-(N-ethylcarboxamide); D000431:Ethanol; D000242:Cyclic AMP; D000241:Adenosine