A novel tubulin-dependent protein kinase forming a paired helical filament epitope on tau.
From rat brain microtubule proteins, we purified a protein kinase that phosphorylated tau, one of microtubule-associated proteins. The electrophoretic mobility of the phosphorylated tau on SDS-polyacrylamide gel decreased. The enzyme was not activated by cyclic nucleotides, calmodulin, or phospholipids, and was inhibited by the calcium ions. The kinase bound to tau. The phosphorylation of tau was stimulated by tubulin under the condition of microtubule formation. From these results we propose an idea that the phosphorylation could occur concomitantly with microtubule formation in the brain. Human tau phosphorylated by the kinase carried an epitope of the paired helical filaments that accumulate in the brain in Alzheimer's disease.
Ishiguro
K
K
Mitsubishikasei Institute of Life Sciences, Tokyo.
Ihara
Y
Y
Uchida
T
T
Imahori
K
K
D000818:Animals; D000939:Epitopes / Q000302:isolation & purification*; D008869:Microtubule-Associated Proteins / Q000276:immunology*; D009419:Nerve Tissue Proteins / Q000276:immunology*; D010766:Phosphorylation; D011487:Protein Conformation; D011494:Protein Kinases / Q000276:immunology* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D015290:Second Messenger Systems; D014404:Tubulin / Q000378:metabolism*; D016875:tau Proteins
D000939:Epitopes; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D014404:Tubulin; D016875:tau Proteins; D011494:Protein Kinases