Ca2+ uptake and IP3-induced Ca2+ release in permeabilized human lymphocytes.
The 45Ca2+ uptake and 45Ca2+ release in saponin-permeabilized human lymphocytes were studied. An ATP-dependent Ca2+ uptake into a nonmitochondrial, intracellular Ca2+ store is observed which is approx. 2 orders of magnitude greater than the ATP-independent Ca2+ uptake. The Ca2+ uptake is inhibited by vanadate, but it is insensitive to oligomycin and ruthenium red. IP3 induces dose-dependent 45Ca2+ release. For half-maximum Ca2+ release 0.25-0.5 microM IP3 is required. The results of our studies suggest that 45Ca2+ is predominantly stored within the endoplasmic reticulum of the lymphocytes.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D001692:Biological Transport; D002118:Calcium / Q000097:blood* / Q000493:pharmacokinetics; D002463:Cell Membrane Permeability; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000494:pharmacology*; D008214:Lymphocytes / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D013403:Sugar Phosphates / Q000494:pharmacology*; D014638:Vanadates / Q000494:pharmacology
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D014638:Vanadates; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D002118:Calcium