title: S100B protein stimulates calcineurin activity.
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.
authors.affiliation: Departamento de Bioquímica, Universidade Federal de Santa Catarina, Brazil.
authors.forename: Rodrigo B
authors.initials: RB
authors.lastname: Leal
authors.forename: Juliana K
authors.initials: JK
authors.lastname: Frizzo
authors.forename: Francine
authors.initials: F
authors.lastname: Tramontina
authors.forename: Sabine
authors.initials: S
authors.lastname: Fieuw-Makaroff
authors.forename: Larisa
authors.initials: L
authors.lastname: Bobrovskaya
authors.forename: Peter R
authors.initials: PR
authors.lastname: Dunkley
authors.forename: Carlos-Alberto
authors.initials: CA
authors.lastname: Gonçalves
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D019703:Calcineurin / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism* / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D003598:Cytoskeletal Proteins; D004791:Enzyme Inhibitors; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579158:S100b protein, rat; D019703:Calcineurin; D002118:Calcium