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Phosphorylation Sites on Tau Identified by Nanoelectrospray Mass Spectrometry
Author(s) -
Reynolds C. Hugh,
Betts Joanna C.,
Blackstock Walter P.,
Nebreda Angel R.,
Anderton Brian H.
Publication year - 2000
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2000.0741587.x
Subject(s) - kinase , phosphorylation , gsk 3 , mitogen activated protein kinase , p38 mitogen activated protein kinases , phosphatase , mapk14 , hyperphosphorylation , microbiology and biotechnology , chemistry , biochemistry , biology , protein kinase a , map kinase kinase kinase
The stress‐activated kinases c‐Jun N‐terminal kinase (JNK)and p38 are members of the mitogen‐activated protein (MAP) kinase family andtake part in signalling cascades initiated by various forms of stress. Theirtargets include the microtubule‐associated protein tau, which becomeshyperphosphorylated in Alzheimer's disease. It is necessary, as a forerunnerfor in vivo studies, to identify the protein kinases and phosphatases that areresponsible for phosphate turnover at individual sites. Using nanoelectrospraymass spectrometry, we have undertaken an extensive comparison ofphosphorylation in vitro by several candidate tau kinases, namely, JNK, p38,ERK2, and glycogen synthase kinase 3β (GSK3β). Between 10 and 15sites were identified for each kinase. The three MAP kinases phosphorylatedSer 202 and Thr 205 but not detectably Ser 199 ,whereas conversely GSK3β phosphorylated Ser 199 but notdetectably Ser 202 or Thr 205 . PhosphorylatedSer 404 was found with all of these kinases except JNK. The MAPkinases may not be strictly proline specific: p38 phosphorylated thenonproline sites Ser 185 , Thr 245 , Ser 305 , andSer 356 , whereas ERK2 was the most strict. All of the sites detectedexcept Thr 245 and Ser 305 are known or suspected phosphorylation sites in paired helical filament‐tau extracted from Alzheimer brains. Thus, the three MAP kinases and GSK3β are importantly all strong candidates as tau kinases that may be involved in the pathogenic hyperphosphorylation of tau in Alzheimer's disease.