The immunofluorescent localization of regulatory and catalytic subunits of cyclic AMP-dependent protein kinase in neuronal and glial cell types of the central nervous system

Abstract

The cellular localization of the regulatory (RI and RII) and catalytic components of the cyclic AMP-dependent protein kinase in selected areas of the central nervous system was determined using a selective and sensitive immunofluorescent technique. The neuronal and glial distribution was similar for the three subunits, however, each unit exhibited differences in the pattern of subcellular localization. Whereas the catalytic unit was confined to intranuclear loci, RI and RII were identified within both the cytoplasm and nucleus, with RII in addition showing distinct staining of the nuclear membrane. A granular distribution of RI in the cell soma further distinguished the cytological localization of these two regulatory components in this cellular compartment. The contrasting distribution of the subunits suggests possible functional differences between the regulatory and catalytic components of cyclic AMP-dependent protein kinase, which are discussed with regard to the role of this enzyme in mediating the physiological effects of cyclic AMP in the central nervous system.