Effect of thimerosal on cytosolic calcium and phosphatidylserine synthesis in Jurkat T cells

1. We investigated the effect of the thiol reagent, thimerosal on calcium movements in the Jurkat T cell line. 2. Thimerosal induced a rise in cytosolic Ca2+ concentration due both to a release of Ca2+ from intracellular stores and a Ca2+ influx. 3. Thimerosal, released Ca2+ from the same intracellular stores than CD3 mAb and ionomycin. 4. Emptying the Ca2+ intracellular stores was accompanied by a marked decrease of phosphatidylserine synthesis indicating that phosphatidylserine synthesis occurs within or close to the endoplasmic reticulum Ca(2+)-stores as previously described in CD3-, ionomycin- or Ca(2+)-ATPase inhibitor-treated lymphocytes.