Thapsigargin-induced Ca2+ release from sarcoplasmic reticulum and asolectin vesicles.
Thapsigargin, an inhibitor of several isoforms of the Ca(2+)-ATPase protein, has been used in many cell preparations to induce an increase in cytosolic Ca2+ concentration purportedly by inhibition of the catalytic cycle. We report in this paper, that thapsigargin induces rapid Ca2+ release from sarcoplasmic reticulum vesicles at concentrations higher than those required to inhibit ATPase activity. Thapsigargin also induces a similar concentration-dependent release in Ca(2+)-loaded asolectin liposomes devoid of any protein. These data suggest that Ca2+ release induced by micromolar concentrations of thapsigargin is due to an ionophoric effect on the lipid membrane.
Favero
T G
TG
Department of Physics, Portland State University, Oregon.
Abramson
J J
JJ
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000737:chemistry / Q000378:metabolism*; D013729:Terpenes / Q000378:metabolism / Q000494:pharmacology*; D019284:Thapsigargin
D008563:Membrane Lipids; D013729:Terpenes; D019284:Thapsigargin; D000251:Adenosine Triphosphatases; D002118:Calcium