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Calcium store depletion in dimethyl BAPTA‐loaded human platelets increases protein tyrosine phosphorylation in the absence of a rise in cytosolic calcium
Author(s) -
Sargeant P,
Farndale RW,
Sage SO
Publication year - 1994
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1994.sp003762
Subject(s) - thapsigargin , tyrosine phosphorylation , phosphorylation , tyrosine , cytosol , protein tyrosine phosphatase , bapta , calcium , microbiology and biotechnology , intracellular , protein phosphorylation , chemistry , fura 2 , biochemistry , biology , protein kinase a , enzyme , organic chemistry
The endomembrane Ca(2+)‐ATPase inhibitor, thapsigargin, was used to deplete the intracellular Ca2+ stores of fura‐2‐loaded human platelets. In control cells, thapsigargin evoked a rise in cytosolic [Ca2+] and a substantial increase in protein tyrosine phosphorylation. Thapsigargin also evoked an increase in tyrosine phosphorylation in cells co‐loaded with fura‐2 and the Ca2+ chelator dimethyl BAPTA, such that the rise in cytosolic [Ca2+] was abolished. These data support the existence of a tyrosine phosphatase regulated by the Ca2+ content of the intracellular store, a requirement of the putative model for reciprocal control of Ca2+ entry by cytosolic and store [Ca2+] via protein tyrosine phosphorylation.