Localization and Developmental Changes of τ Protein Kinase I/Glycogen Synthase Kinase-3β in Rat Brain
Article first published online: 23 NOV 2002
Journal of Neurochemistry
Volume 63, Issue 1, pages 245–255, July 1994
How to Cite
Takahashi, M., Tomizawa, K., Kato, R., Sato, K., Uchida, T., Fujita, S. C. and Imahori, K. (1994), Localization and Developmental Changes of τ Protein Kinase I/Glycogen Synthase Kinase-3β in Rat Brain. Journal of Neurochemistry, 63: 245–255. doi: 10.1046/j.1471-4159.1994.63010245.x
- Issue published online: 23 NOV 2002
- Article first published online: 23 NOV 2002
- Received September 17, 1993; revised manuscript received November 3, 1993; accepted November 3, 1993.
- τ protein kinase I;
- Glycogen synthase kinase;
- Developmental changes;
- Rat brain
Abstract: τ protein kinase I (TPKI) purified from bovine brain extract has been shown to phosphorylate τ and to form paired helical filament (PHF) epitopes and was found recently to be identical to glycogen synthase kinase-3β (GSK-3β). Before elucidating a role of TPKI/GSK-3β in PHF formation, it is necessary to investigate the normal function of the enzyme. To study the distribution and developmental changes of the enzyme, specific polyclonal antibodies were prepared against TPKI and GSK-3α. Immunoblot analysis demonstrated that TPKI was nearly specifically localized in the brain of adult rats. The level of TPKI in the rat brain was high at gestational day 18, peaked on postnatal day 8, and then decreased rapidly to a low level, which was sustained up to 2 years. Immunohistochemistry indicated primarily neuronal localization of TPKI. Growing axons were stained most intensely in the developing cerebellum, but the immunoreactivity became restricted to the gray matter in the mature tissue. Parallel fibers had a high level of TPKI and also stained intensely for τ. These findings indicate that τ is one of the physiological substrates of TPKI and suggest that the enzyme plays an important role in the growth of axons during development of the brain.