14-3-3 connects glycogen synthase kinase-3 beta to tau within a brain microtubule-associated tau phosphorylation complex.
In a recent study, we reported that in bovine brain extract, glycogen synthase kinase-3beta and tau are parts of an approximately 400-500 kDa microtubule-associated tau phosphorylation complex (Sun, W., Qureshi, H. Y., Cafferty, P. W., Sobue, K., Agarwal-Mawal, A., Neufield, K. D., and Paudel, H. K. (2002) J. Biol. Chem. 277, 11933-11940). In this study, we find that when purified brain microtubules are subjected to Superose 12 gel filtration column chromatography, the dimeric scaffold protein 14-3-3 zeta co-elutes with the tau phosphorylation complex components tau and GSK3 beta. From gel filtration fractions containing the tau phosphorylation complex, 14-3-3 zeta, GSK3 beta, and tau co-immunoprecipitate with each other. From extracts of bovine brain, COS-7 cells, and HEK-293 cells transfected with GSK3 beta, 14-3-3 zeta co-precipitates with GSK3 beta, indicating that GSK3 beta binds to 14-3-3 zeta. From HEK-293 cells transfected with tau, GSK3 beta, and 14-3-3 zeta in different combinations, tau co-immunoprecipitates with GSK3 beta only in the presence of 14-3-3 zeta. In vitro, approximately 10-fold more tau binds to GSK3 beta in the presence of than in the absence of 14-3-3 zeta. In transfected HEK-293 cells, 14-3-3 zeta stimulates GSK3 beta-catalyzed tau phosphorylation in a dose-dependent manner. These data indicate that in brain, the 14-3-3 zeta dimer simultaneously binds and bridges tau and GSK3 beta and stimulates GSK3 beta-catalyzed tau phosphorylation.
Agarwal-Mawal
Alka
A
Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada.
Qureshi
Hamid Y
HY
Cafferty
Patrick W
PW
Yuan
Zongfei
Z
Han
Dong
D
Lin
Rongtian
R
Paudel
Hemant K
HK
D048948:14-3-3 Proteins; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D019556:COS Cells; D002417:Cattle; D002458:Cell Fractionation; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D017931:DNA Primers; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D010766:Phosphorylation; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D016875:tau Proteins / Q000378:metabolism*
D048948:14-3-3 Proteins; D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D016875:tau Proteins; D014446:Tyrosine 3-Monooxygenase; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3