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Vanadium salts stimulate mitogen-activated protein (MAP) kinases and ribosomal S6 kinases
S K Pandey1, J L Chiasson, A K Srivastava
1Centre de Recherche/Hotel-Dieu de Montreal Hospital, Quebec, Canada.
Abstract:
Effect of several vanadium salts, sodium orthovanadate, vanadyl sulfate and sodium metavanadate on protein tyrosine phosphorylation and serine/threonine kinases in chinese hamster ovary (CHO) cells overexpressing a normal human insulin receptor was examined. All the compounds stimulated protein tyrosine phosphorylation of two major proteins with molecular masses of 42 kDa (p42) and 44 kDa (p44). The phosphorylation of p42 and p44 was associated with an activation of mitogen activated protein (MAP) kinase as well as increased protein tyrosine phosphorylation of p42mapk and p44mapk. Vanadium salts also activated the 90 kDa ribosomal s6 kinase (p90rsk) and 70 kDa ribosomal s6 kinase (p70s6k). Among the three vanadium salts tested, vanadyl sulfate appeared to be slightly more potent than others in stimulating MAP kinases and p70s6k activity. It is suggested that vanadium-induced activation of MAP kinases and ribosomal s6 kinases may be one of the mechanisms by which insulin like effects of this trace element are mediated.
Insights
Vanadium salts, including vanadyl sulfate, activate protein tyrosine phosphorylation and key kinases like MAP kinase and ribosomal s6 kinase in CHO cells. This suggests a mechanism for vanadium's insulin-like effects.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Vanadium compounds are known to exhibit insulin-mimetic properties.
- Protein tyrosine phosphorylation and kinase activation are crucial signaling pathways in cellular regulation.
- Chinese Hamster Ovary (CHO) cells overexpressing human insulin receptors provide a model for studying insulin signaling.
Purpose of the Study:
- To investigate the effects of various vanadium salts on protein tyrosine phosphorylation and serine/threonine kinases.
- To determine the specific kinases affected by vanadium treatment in CHO cells.
- To elucidate the potential mechanisms underlying vanadium's insulin-like actions.
Main Methods:
- Treatment of CHO cells overexpressing human insulin receptors with sodium orthovanadate, vanadyl sulfate, and sodium metavanadate.
- Analysis of protein tyrosine phosphorylation levels of specific proteins.
- Assay of mitogen-activated protein (MAP) kinase, p90 ribosomal s6 kinase (p90rsk), and 70 kDa ribosomal s6 kinase (p70s6k) activities.
Main Results:
- All tested vanadium salts stimulated protein tyrosine phosphorylation of 42 kDa (p42) and 44 kDa (p44) proteins.
- Vanadium treatment led to the activation of MAP kinase, evidenced by increased phosphorylation of p42mapk and p44mapk.
- Vanadium salts also activated p90rsk and p70s6k, with vanadyl sulfate showing slightly higher potency.
Conclusions:
- Vanadium salts effectively induce protein tyrosine phosphorylation and activate MAP kinases and ribosomal s6 kinases in CHO cells.
- Vanadyl sulfate demonstrated a notable potency in stimulating these kinase activities.
- The activation of MAP kinases and ribosomal s6 kinases by vanadium may represent a key mechanism for its insulin-like effects.