The Role of Protein Phosphorylation and dephosphorylation in Neuronal Signal Transduction

点击翻译按钮获取中文摘要

Recently, protein phosphorylation and dephosphorylation are thought to be a central event in cellular signal transduction. Large amount of protein kinases and protein phosphatases are found in the central nervous system, suggesting that these enzymes are involved in the neuronal signal transduction. In this fiscal year, we obtained following findings on the protein kinase C and calcineurin.1) Developmental change in the distribution of protein kinase C subspecies in rat brain was examined. alpha and beta I subspecies were found when rat was born, on the other hand, beta II and gamma subspecies appeared one to two weeks after the birth when the synaptogenesis occurred.2) Immunohistochemical study on the localization of four protein kinase C subspecies and neurotransmitters in striate-nigral system was performed. Dopaminergic neurons in the substantia nigra and cholinergic neurons in the striatum contained alpha subspecies, and GABAergic neurons in the striatum contained beta -I subspecies.3) Distribution of calcineurin A subtypes were examined using in situ hybridization technique and immunohistochemistry in rat brain. The activation mechanism of calcineurin was studied usign calmodulin antagonists.4) GABA_B receptor was expressed in Xenopus oocyte and its regulation by protein kinase C was demonstrated.5) cDNA cloning of testis-specific calcineurin B-like protein and cDNA cloning of yeast homolog of calcineurin B were performed.