RRC ID 55958
Author Hishinuma S, Komazaki H, Tsukamoto H, Hatahara H, Fukui H, Shoji M.
Title Ca2+ -dependent down-regulation of human histamine H1 receptors in Chinese hamster ovary cells.
Journal J Neurochem
Abstract Gq/11 protein-coupled human histamine H1 receptors in Chinese hamster ovary cells stimulated with histamine undergo clathrin-dependent endocytosis followed by proteasome/lysosome-mediated down-regulation. In this study, we evaluated the effects of a sustained increase in intracellular Ca2+ concentrations induced by a receptor-bypassed stimulation with ionomycin, a Ca2+ ionophore, on the endocytosis and down-regulation of H1 receptors in Chinese hamster ovary cells. All cellular and cell-surface H1 receptors were detected by the binding of [3 H]mepyramine to intact cells sensitive to the hydrophobic and hydrophilic H1 receptor ligands, mepyramine and pirdonium, respectively. The pretreatment of cells with ionomycin markedly reduced the mepyramine- and pirdonium-sensitive binding sites of [3 H]mepyramine, which were completely abrogated by the deprivation of extracellular Ca2+ and partially by a ubiquitin-activating enzyme inhibitor (UBEI-41), but were not affected by inhibitors of calmodulin (W-7 or calmidazolium) and protein kinase C (chelerythrine or GF109203X). These ionomycin-induced changes were also not affected by inhibitors of receptor endocytosis via clathrin (hypertonic sucrose) and caveolae/lipid rafts (filipin or nystatin) or by inhibitors of lysosomes (E-64, leupeptin, chloroquine, or NH4 Cl), proteasomes (lactacystin or MG-132), and a Ca2+ -dependent non-lysosomal cysteine protease (calpain) (MDL28170). Since H1 receptors were normally detected by confocal immunofluorescence microscopy with an antibody against H1 receptors, even after the ionomycin treatment, H1 receptors appeared to exist in a form to which [3 H]mepyramine was unable to bind. These results suggest that H1 receptors are apparently down-regulated by a sustained increase in intracellular Ca2+ concentrations with no process of endocytosis and lysosomal/proteasomal degradation of receptors.
Volume 144(1)
Pages 68-80
Published 2018-1
DOI 10.1111/jnc.14245
PMID 29063596
MeSH Animals Astrocytoma CHO Cells Calcium / pharmacology* Calcium Ionophores / pharmacology Calcium Signaling / drug effects Calcium Signaling / physiology* Calmodulin / antagonists & inhibitors Calpain / antagonists & inhibitors Cell Line, Tumor Cricetinae Cricetulus Down-Regulation / drug effects Endocytosis / drug effects Histamine / pharmacology Humans Inositol Phosphates / metabolism Ionomycin / pharmacology Lysosomes / drug effects Membrane Microdomains / drug effects Proteasome Endopeptidase Complex / drug effects Protein Kinase Inhibitors / pharmacology Pyrilamine / metabolism Receptors, Histamine H1 / biosynthesis* Receptors, Histamine H1 / genetics Recombinant Proteins / biosynthesis
IF 4.87
Times Cited 1
Human and Animal Cells CHO-K1(RCB0285)