Depletion of intracellular calcium stores triggers transplasmamembrane chloride influx in human lymphocytes: regulation by tyrosine kinase.
The capacitative regulation of intracellular chloride concentration ([Cl-]i) was measured in intact human lymphocytes using the Cl(-)-sensitive fluorescence dye 6-methoxy-1-(3-sulfonato-propyl)-quinolinium (SPQ). The fluorescence was measured at 433 nm with the excitation wavelength of 344 nm. The emptying of intracellular Ca2+ stores after the specific inhibition of the endoplasmic Ca2+ ATPase by thapsigargin produced a concentration-dependent transplasmamembrane Cl- influx. The thapsigargin-induced Cl- increase was also seen in the absence of extracellular Ca2+, but it was significantly reduced after the addition of the Cl- exchange blocker, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. The thapsigargin-induced Cl- increase was significantly reduced after the specific inhibition of tyrosine kinase by genistein or tyrphostin A25. It is concluded that the depletion of intracellular Ca2+ pools triggers transplasmamembrane Cl- influx by a tyrosine kinase-dependent mechanism.
Tepel
M
M
Medizinische Universitäts-Poliklinik, University of Münster, Germany.
Hahne
G
G
Zidek
W
W
D001692:Biological Transport; D002118:Calcium / Q000502:physiology*; D002396:Catechols / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D005456:Fluorescent Dyes; D019833:Genistein; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011806:Quinolinium Compounds; D013050:Spectrometry, Fluorescence; D020032:Tyrphostins
D002396:Catechols; D002712:Chlorides; D005456:Fluorescent Dyes; D007529:Isoflavones; D009570:Nitriles; D011806:Quinolinium Compounds; D020032:Tyrphostins; C060152:tyrphostin 47; C052335:6-methoxy-N-(3-sulfopropyl)quinolinium; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D002118:Calcium