Heterologous, PKC-Mediated Desensitization of Human Histamine H3 Receptors Expressed in CHO-K1 Cells.

Heterologous, PKC-Mediated Desensitization of Human Histamine H3 Receptors Expressed in CHO-K1 Cells. Neurochem Res. 2016 Jun 27; Authors: Montejo-López W, Rivera-Ramírez N, Escamilla-Sánchez J, García-Hernández U, Arias-Montaño JA Abstract Desensitization is a major mechanism to regulate the functional response of G protein-coupled receptors. In this work we studied whether the human histamine H3 receptor of 445 amino acids (hH3R445) experiences heterologous desensitization mediated by PKC activation. Bioinformatic analysis indicated the presence of Serine and Threonine residues susceptible of PKC-mediated phosphorylation on the third intracellular loop and the carboxyl terminus of the hH3R445. In CHO-K1 cells stably transfected with the hH3R445 direct PKC activation by phorbol 12-myristate 13-acetate (TPA, 200 nM) abolished H3R-mediated inhibition of forskolin-stimulated cAMP accumulation. Activation of endogenous purinergic receptors by ATP (adenosine 5'-triphosphate, 10 μM) increased the free calcium intracellular concentration ([Ca(2+)]i) confirming their coupling to phospholipase C stimulation. Incubation with ATP also abolished H3R-mediated inhibition of forskolin-induced cAMP accumulation, and this effect was prevented by the PKC inhibitors Ro-31-8220 and Gö-6976. Pre-incubation with TPA or ATP reduced H3R-mediated stimulation of [(35)S]-GTPγS binding to membranes from CHO-K1-hH3R445 cells by 39.7 and 54.2 %, resp...
Source: Neurochemical Research - Category: Neuroscience Authors: Tags: Neurochem Res Source Type: research