DIFFERENT LOCALIZATION OF TAU-PROTEIN-KINASE-I GLYCOGEN-SYNTHASE KINASE-3-BETA FROM GLYCOGEN-SYNTHASE KINASE-3-ALPHA IN CEREBELLUM MITOCHONDRIA

We examined the subcellular distribution of two glycogen synthase kina se-3 (GSK-3) isoforms in rat cerebellum, Results from immunoelectron m icroscopy and subcellular fractionation revealed that one isoform, tau protein kinase I/GSK-3 beta (TPKI/GSK-3 beta), was present in mitocho ndria, but GSK-3 alpha was not, Although the two GSK-3 isoforms seem t o have similar properties, the difference of subcellular localization observed here suggests that TPKI/GSK-3 beta fulfills some specific fun ction in mitochondria.