Abstract
S100B is a calcium binding protein from astrocytes that regulates protein phosphorylation by binding to substrates and protein kinases. S100B might also regulate protein phosphatases and this was investigated for protein phosphatase 2B (calcineurin). The results indicate that S100B (5-10 microM) increased the activity of both purified and cytoskeletal calcineurin in a Ca-dependent manner. This effect was blocked by a specific inhibitor of calcineurin activity, but not by TRTK-12 (an inhibitor of S100B binding to other protein targets). The present results and the known co-localization of S100B and calcineurin in the astrocyte cytoskeleton suggest that S100B may play a role in the phosphorylation state of cytoskeletal proteins.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Newborn
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Astrocytes / drug effects
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Astrocytes / enzymology*
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Astrocytes / ultrastructure
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Calcineurin / drug effects
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Calcineurin / metabolism*
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Calcium / metabolism
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Calcium Signaling / drug effects
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Calcium Signaling / physiology
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Cells, Cultured
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Cytoskeletal Proteins / drug effects
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Cytoskeletal Proteins / metabolism*
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Enzyme Inhibitors / pharmacology
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Nerve Growth Factors / metabolism*
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Nerve Growth Factors / pharmacology
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Phosphorylation / drug effects
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Rats
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Rats, Wistar
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S100 Calcium Binding Protein beta Subunit
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S100 Proteins / metabolism*
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S100 Proteins / pharmacology
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Up-Regulation / drug effects
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Up-Regulation / physiology
Substances
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Cytoskeletal Proteins
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Enzyme Inhibitors
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Nerve Growth Factors
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S100 Calcium Binding Protein beta Subunit
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S100 Proteins
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S100b protein, rat
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Calcineurin
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Calcium