FRAT-2 preferentially increases glycogen synthase kinase 3 beta-mediated phosphorylation of primed sites, which results in enhanced tau phosphorylation
| Autor: | William H. Stoothoff, Roy P. McDonald, Jae-Hyeon Cho, Gail V.W. Johnson |
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| Rok vydání: | 2004 |
| Předmět: |
inorganic chemicals
Protein family tau Proteins macromolecular substances environment and public health Biochemistry Epitope law.invention Cell Line Substrate Specificity Epitopes Glycogen Synthase Kinase 3 GSK-3 law Cricetinae Animals Humans Phosphorylation Molecular Biology Binding Sites Glycogen Synthase Kinase 3 beta Chemistry In vitro toxicology Substrate (chemistry) Cell Biology Molecular biology Recombinant Proteins Neoplasm Proteins Rats Enzyme Activation enzymes and coenzymes (carbohydrates) Recombinant DNA bacteria Carrier Proteins Function (biology) |
| Zdroj: | The Journal of biological chemistry. 280(1) |
| ISSN: | 0021-9258 |
| Popis: | Tau is a microtubule-associated protein found primarily in neurons, and its function is regulated by site-specific phosphorylation. Although it is well established that tau is phosphorylated at both primed and unprimed epitopes by glycogen synthase kinase 3 beta (GSK3 beta), how specific proteins that interact with GSK3 beta regulate tau phosphorylation has not been thoroughly examined. Members of the FRAT (frequently rearranged in advanced T-cell lymphoma) protein family have been shown to interact with GSK3 beta, and FRAT-1 has been shown to modulate the activity of GSK3 beta toward tau and other substrates. However, the effects of FRAT-2 on GSK3 beta activity and tau phosphorylation have not been examined. Therefore in this study the effects of FRAT-2 on GSK3 beta activity and tau phosphorylation were examined. In situ, FRAT-2 significantly increased GSK3 beta-mediated phosphorylation of tau at a primed epitope while not significantly affecting the phosphorylation of unprimed sites. Co-immunoprecipitation studies revealed that association of FRAT-2 with GSK3 beta resulted in a significant increase in phosphorylation of a primed substrate but did not alter phosphorylation of an unprimed substrate. Further, in vitro assays using recombinant proteins directly demonstrated that FRAT-2 enhances GSK3 beta-mediated phosphorylation of a primed substrate to a greater extent than an unprimed substrate. In addition, FRAT-2 is phosphorylated by GSK3 beta. This is the first demonstration of a protein differentially regulating the activity of GSK3 beta toward primed and unprimed epitopes. |
| Databáze: | OpenAIRE |
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