Calcium release activated calcium entry in a human skin derived cell line (HaCaT).
Using isolated cells from a spontaneously immortalized human keratinocyte cell line (HaCaT) loaded with Fura-2 the regulation of intracellular Ca2+ concentration ([Ca2+]i) was studied. The continuous presence of ATP induced a biphasic response in high external Ca2+. The first component reflected the release of calcium from intracellular stores since it was present after the removal of external calcium with ethylene-glycol-bis-N,N,N',N'-tetraacetic acid (EGTA). The second phase of [Ca2+]i increase was not detectable in the absence of external calcium and raising the extracellular [Ca2+] increased the rate of rise in [Ca2+]i suggesting that it was influenced by the external environment. Furthermore, after adenosine triphosphate (ATP) had emptied the intracellular store in a calcium-free milieu, the elevation of external Ca2+ induced a secondary increase in [Ca2+]i that did not require the presence of ATP. Depleting the intracellular calcium store with a Ca-ATP-ase inhibitor (cyclopiasonic acid, 10 microM) also induced calcium entry. The depletion induced calcium entry was inhibited by econazole (100 microM). These findings indicate the presence of a calcium release activated calcium influx pathway in HaCaT keratinocytes.
Csernoch
L
L
Department of Physiology, University Medical School, Debrecen, Hungary. CSL@PHYS.DOTE.HU
Hunyadi
J
J
Kovács
L
L
D000255:Adenosine Triphosphate / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002460:Cell Line; D004464:Econazole / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*
D004791:Enzyme Inhibitors; D007211:Indoles; D004464:Econazole; D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases; D002118:Calcium; C000543:cyclopiazonic acid