Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P46098 (5-HT3 receptor)
 2,290 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of agents that activate or inhibit protein kinase C (PKC) on the function of recombinant 5-HT3 receptors expressed in Xenopus oocytes was studied. The PKC activator phorbol 12-myristate 13-acetate (PMA) induced a long-lasting increase in the amplitude of 5-HT-activated ion current. The potentiation was maximal at 20 min and had a duration of approximately 60 min. The inactive phorbol ester, 4 alpha-PMA, had no effect on 5-HT3 receptor-mediated current. The PMA-induced potentiation was concentration-dependent over the concentration range 0.1-300 nM. The percentage potentiation by PMA was maximal at low 5-HT concentrations and decreased with increasing concentrations of 5-HT. For current activated by 0.1 microM 5-HT, maximal potentiation (Emax) was 667% of control, the EC50 was 15 nM and the apparent Hill coefficient was 0.99. The PKC inhibitor, staurosporin, antagonized the PMA potentiation; whereas, inhibitors of protein kinase A (PKA) or tyrosine kinase had no effect on this potentiation. The observations show that PMA can potentiate 5-HT3 receptor-mediated responses and suggest that this potentiation is mediated by activation of PKC.
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PMID:Potentiation of 5-HT3 receptor-mediated responses by protein kinase C activation. 748 49

The effects of phorbol 12-myristate, 13-acetate (PMA) on 5-hydroxytryptamine (5-HT)-evoked ion currents in the mouse 5-HT3A receptor were examined. Perfusion with PMA caused a concentration dependent potentiation of 5-HT mediated currents and increased both potency and efficacy of 5-HT at the 5-HT3A receptor expressed in Xenopus oocytes. Enhancement of receptor function was partially blocked by injection of oocytes with PKCI, the peptide inhibitor of protein kinase C (PKC). Mutation of all 12 intracellular serine and threonine residues to alanine was without effect on PMA-induced potentiation of 5-HT elicited currents. Mutation of tyrosine 458 in the 5-HT3A receptor lacking intracellular serines and threonines reduced the PMA-induced potentiation of 5-HT evoked currents by approximately 55%. In contrast, mutation of tyrosine 458 in the wild-type receptor did not alter PMA-induced enhancement. The tyrosine kinase inhibitor, lavendustin A, reduced the enhancement of 5-HT3A receptor mediated currents by PMA in the mutant 5-HTA3A receptor containing no intracellular serine or threonine residues, but not in the wild-type receptor. Thus, the role of intracellular serines and threonines is redundant with that of tyrosine, suggesting that these two components act through a similar pathway in response to PMA treatment.
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PMID:Enhancement of 5-hydroxytryptamine3A receptor function by phorbol 12-myristate, 13-acetate is mediated by protein kinase C and tyrosine kinase activity. 1244 87