Biochemical characterization of tau protein and its associated syndapin 1 and protein kinase Cepsilon for their functional regulation in rat brain.
BACKGROUND
We recently reported that both sulfatide and cholesterol-3-sulfate (SCS) function as potent stimulators for the GSK-3beta-mediated phosphorylation of tau protein (TP) in vitro [J. Biochem. 143 (2008) 359-367].


METHODS
By means of successive gel filtration on a Superdex 200 pg column and three distinct ion-exchange column chromatographies, TP and its associated proteins were highly purified from the extract of rat brain.


RESULTS
We found that (i) syndapin 1 and novel protein kinase Cepsilon (nPKCepsilon) were identified as the TP-associated proteins; (ii) SCS highly stimulated the phosphorylation of TP and syndapin 1 by nPKCepsilon as well as CK1; (iii) the full phosphorylation of TP and syndapin 1 by nPKCepsilon in the presence of sulfatide resulted in their dissociation; (iv) TP primed by CK1 functioned as an effective phosphate acceptor for GSK-3beta; (v) syndapin 1 highly stimulated the GSK-3beta-mediated phosphorylation of TP; and (vi) TP isoforms were highly expressed in aged brain, whereas syndapin 1 was consistently detected in adult brain, but not in newborn brain.


CONCLUSIONS
These results provided here suggest that (i) TP-associated nPKCepsilon suppresses the GSK-3beta-mediated phosphorylation of TP through the phosphorylation of GSK-3beta by the kinase in vitro; and (ii) SCS act as effective sole mediators to induce the GSK-3beta-mediated high phosphorylation of both TP and its associated syndapin 1 involved in the biochemical processes of neuronal diseases, including Alzheimer's disease.
Suzuki
Kanzo
K
Laboratory of Molecular Signal Biology, Graduate School of Medical Sciences, Kitasato University, Sagamihara 228-8555, Japan.
Kawakami
Fumitaka
F
Sasaki
Hisashi
H
Maruyama
Hiroko
H
Ohtsuki
Kenzo
K
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003598:Cytoskeletal Proteins; D047468:Immunoprecipitation; D010766:Phosphorylation; D011485:Protein Binding; D051744:Protein Kinase C-epsilon / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity; D016875:tau Proteins / Q000378:metabolism*
D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C117738:Pacsin1 protein, rat; D016875:tau Proteins; D051744:Protein Kinase C-epsilon