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Biochemistry. 1990 Nov 6;29(44):10240-5.

A combination of H2O2 and vanadate concomitantly stimulates protein tyrosine phosphorylation and polyphosphoinositide breakdown in different cell lines.

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Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.


Treatment of four cell lines [rat hepatoma (Fao), murine muscle (BC3H-1), Chinese hamster ovary (CHO), and rat basophilic leukemia (RBL)] with a combination of 3 mM H2O2 and 1 mM sodium orthovanadate markedly stimulates protein tyrosine phosphorylation, which is accompanied by a dramatic increase (5-15-fold) in inositol phosphate (InsP) formation. H2O2/vanadate stimulate best formation of inositol triphosphate while their effects on the mono and di derivatives are more moderate. In the presence of 3 mM H2O2, both protein tyrosine phosphorylation and InsP formation are highly correlated and manifest an identical dose-response relationship for vanadate. Half-maximal and maximal effects are obtained at 30 and 100 microM, respectively. This stimulatory effect of H2O2/vanadate is not mimicked by other oxidants such as spermine, spermidine, KMnO4, and vitamin K3. In RBL cells, the kinetics of inositol triphosphate formation correlate with tyrosine phosphorylation of a 67-kDa protein, while tyrosine phosphorylation of a 55-kDa protein is closely correlated with both inositol monophosphate formation and serotonin secretion from these cells. Taken together, these results suggest a causal relationship between tyrosine phosphorylation triggered in a nonhormonal manner and polyphosphoinositide breakdown. Furthermore, these results implicate protein tyrosine phosphorylation in playing a role in the stimulus-secretion coupling in RBL cells.

[Indexed for MEDLINE]

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