title: Modulation of histamine-induced Ca2+ release by protein kinase C. Effects on cytosolic and mitochondrial [Ca2+] peaks.
abstract: In HeLa cells, histamine induces production of inositol 1,4,5-trisphosphate (InsP3) and release of Ca2+ from the endoplasmic reticulum (ER). Ca2+ release is typically biphasic, with a fast and brief initial phase, followed by a much slower and prolonged one. In the presence of inhibitors of protein kinase C (PKC), including staurosporine and the specific inhibitors GF109203X and Ro-31-8220, the fast phase continued until the ER became fully empty. On the contrary, treatment with phorbol 12,13-dibutyrate inhibited Ca2+ release. Staurosporine had no effect on InsP3-induced Ca2+ release in permeabilized cells and did not modify either histamine-induced InsP3 production. These data suggest that histamine induces Ca2+ release and with a short lag activates PKC to down-regulate it. Consistently, Ca2+ oscillations induced by histamine were increased in amplitude and decreased in frequency in the presence of PKC inhibitors. We show also that mitochondrial [Ca2+] was much more sensitive to changes in ER-Ca2+ release induced by PKC modulation than cytosolic [Ca2+]. PKC inhibitors increased the histamine-induced mitochondrial [Ca2+] peak by 4-fold but increased the cytosolic [Ca2+] peak only by 20%. On the contrary, PKC activation inhibited the mitochondrial [Ca2+] peak by 90% and the cytosolic one by only 50%. Similarly, the combination of PKC inhibitors with the mitochondrial Ca2+ uniporter activator SB202190 led to dramatic increases in mitochondrial [Ca2+] peaks, with little effect on cytosolic ones. This suggests that activation of ER-Ca2+ release by PKC inhibitors could be involved in apoptosis induced by staurosporine. In addition, these mechanisms allow flexible and independent regulation of cytosolic and mitochondrial [Ca2+] during cell stimulation.
authors.affiliation: Instituto de Biología y Genética Molecular, Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid and Consejo Superior de Investigaciones Científicas, Ramón y Cajal, 7, E-47005 Valladolid, Spain.
authors.forename: Mayte
authors.initials: M
authors.lastname: Montero
authors.forename: Carmen D
authors.initials: CD
authors.lastname: Lobatón
authors.forename: Silvia
authors.initials: S
authors.lastname: Gutierrez-Fernández
authors.forename: Alfredo
authors.initials: A
authors.lastname: Moreno
authors.forename: Javier
authors.initials: J
authors.lastname: Alvarez
mesh_terms: D000331:Aequorin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology* / Q000378:metabolism; D015536:Down-Regulation; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006632:Histamine / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000737:chemistry; D008301:Maleimides / Q000494:pharmacology; D008928:Mitochondria / Q000201:enzymology*; D009991:Oscillometry; D011493:Protein Kinase C / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D013997:Time Factors; D014162:Transfection
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; D007211:Indoles; D008301:Maleimides; D011725:Pyridines; D000331:Aequorin; D006632:Histamine; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D011493:Protein Kinase C; D019311:Staurosporine; C070515:bisindolylmaleimide I; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole; D002118:Calcium; C064758:Ro 31-8220