title: Extracellular pH modifies mitochondrial control of capacitative calcium entry in Jurkat cells.
abstract: It was found that a collapse of the mitochondrial calcium buffering caused by the protonophoric uncoupler CCCP, antimycin A plus oligomycin, or the inhibitor of the mitochondrial Ca2+/Na+ exchanger led to a strong inhibition of thapsigargin-induced capacitative Ca2+ entry (CCE) into Jurkat cells suspended in a medium at pH 7.2. The effect of these inhibitors was markedly less significant at higher extracellular pH. Moreover, dysfunction of the mitochondrial calcium handling greatly decreased CCE sensitivity to extracellular Ca2+ when the pH of extracellular solution was 7.2 (apparent Kd toward extracellular Ca2+ rose from 2.3 +/- 0.6 mm in control cells to 11.0 +/- 1.7 mM in CCCP-treated cells) as compared with pH 7.8 (apparent Kd toward extracellular Ca2+ increased from 1.3 +/- 0.4 mM in control cells to 2.4 +/- 0.4 mM in uncoupler-treated cells). Changes in intracellular pH triggered by methylamine did not influence Ca2+ influx. This suggests that, in Jurkat cells, store-operated calcium channels sense extracellular pH change as a parameter that modifies their sensitivity to intracellular Ca2+. In contrast, in human osteosarcoma cells, changes in extracellular pH as well as mitochondrial uncoupling did not exert any inhibitory effects on CCE.
authors.affiliation: Nencki Institute of Experimental Biology, Pasteura 3, 02-093 Warsaw, Poland. k.zablocki@nencki.gov.pl
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Zabłocki
authors.forename: Joanna
authors.initials: J
authors.lastname: Szczepanowska
authors.forename: Jerzy
authors.initials: J
authors.lastname: Duszyński
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000968:Antimycin A / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002998:Clonazepam / Q000031:analogs & derivatives* / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019169:Jurkat Cells / Q000187:drug effects / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009840:Oligomycins / Q000494:pharmacology; D012516:Osteosarcoma; D013841:Thiazepines / Q000494:pharmacology; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D009840:Oligomycins; D013841:Thiazepines; D014475:Uncoupling Agents; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D002998:Clonazepam; D000968:Antimycin A; C079032:CGP 37157; D002118:Calcium