Immunocytochemical localization of protein kinase C isozymes in rat brain

Abstract

Recently, we isolated 3 protein kinase C (PKC) isozymes from rat brain (Huang et al., 1986a). Using isozyme-specific antibodies for immunoblot, we have determined the relative levels of each isozyme in various regions of the rat brain (Huang et al., 1987b). The present paper describes the cellular distributions of PKC isozymes in rat brain as determined by light microscopic immunocytochemistry. Staining with PKC antibodies revealed strong immunoreactivities in neuronal somata and their dendrites and weak to no reaction in axon and the astroglial structures. In the cerebellum, the type I PKC antibodies stained the Purkinje cell bodies and dendrites; the type II PKC antibodies stained the granule cells; and the type III PKC antibody stained both Purkinje and granule cells. In the cerebral cortex, all antibodies stained neurons resembling pyramidal cells and their apical dendrites in layers II to VI, while layer I was nearly devoid of staining. However, the various isozyme-specific antibodies revealed distinct laminar distribution patterns of the positively stained neurons, and the type III PKC-positive neurons exhibited a higher density than those of type I or II PKC-positive ones, especially in layer II of cingulate (retrosplenial) and piriform cortices. In the hippocampal formation, both pyramidal cells of the hippocampus and granule cells of the dentate gyrus were stained by all PKC antibodies. Subcellularly, type III PKC appeared mostly in the cytoplasm of these neurons, whereas type I and II PKC seemed to associate with the nucleus as well. In the olfactory bulb, both type II and III PKC antibodies stained the periglomerular and granular cells, and the latter also stained the mitral cells. The distinct cellular and subcellular distribution of PKC isozymes suggests that each isozyme plays a unique role in the various neural functions.

Phospholipase Cβ4 is specifically involved in climbing fiber synapse elimination in the developing cerebellum

“…In this respect, PLC␤4 mutant mice share a common phenotype with previously reported mutant mice with inactivated mGluR1, G␣q, or PKC␥ gene (14,15,16). mGluR1, G␣q, and PKC␥ all are expressed abundantly and homogeneously in adult wild-type PCs; mGluR1 is localized on the perisynaptic membrane of PC dendritic spines (4,5), G␣q͞11 is on the extra-junctional membrane of PC dendritic spines (S. Nakagawa, J. Tanaka, M.W., M.K., M.I.S., and Y.I., unpublished data), and PKC␥ is in the cytoplasm of PC dendrites and somata (8,9,10). In the present study, we found that expression of PLC␤4 mRNA is heterogeneous in the rostrocaudal and mediolateral axes (Fig.…”

“…PCs express high levels of type 1 metabotropic glutamate receptor (mGluR1) (4,5), which stimulates PLC through the activation of heterotrimeric G-proteins of the G␣q͞11 family (6,7). PCs are also very rich in the ␥ isoform of protein kinase C (PKC␥) (8,9,10) and in inositol 1,4,5-trisphosphate receptors (11), both of which are activated after hydrolysis of phosphatidylinositol 4,5-bisphosphate by the PLC␤ enzymes. G␣q has been shown to colocalize with mGluR1 in PC dendritic spines (S. Nakagawa, J. Tanaka, M.W., M.K., M.I.S., and Y.I., unpublished data).…”

Involvement of neurogranin in the modulation of calcium/calmodulin-dependent protein kinase II, synaptic plasticity, and spatial learning: A study with knockout mice

“…PKC is the only known Ng kinase in vitro (5), and deletion of PKC ␥ gene in mice negates both the glutamate-and depolarization-mediated phosphorylation of Ng (9). The close functional relationship between Ng and PKC ␥ is further illustrated by their similar developmental expression patterns in the cerebral cortex (10)(11)(12). Previous studies also suggest that Ng plays a critical role in synaptic plasticity.…”

Role of PKCα and PKCι in phenylephrine-induced contraction of rat corpora cavernosa

“…13,29 We did observe a moderate signal for PKCg, an isozyme more often associated with neural tissue, which likely reflects the strong innervation of the cavernosal tissues. 30 Traditionally, PKCs were believed to reside in the cytosol in an inactive conformation and translocate to the membrane (or other subcellular sites) upon activation where they modify various cellular functions through phosphorylation of target substrates. 16,22 We observed that PKCa, b, d, andi were predominantly present in the particulate fraction of rat cavernosal smooth muscle in resting state.…”