Differential Localization of the γ₃ and γ₁₂ Subunits of G Proteins in the Mammalian Brain

Abstract

Abstract:The localization of two forms of the y subunit of G proteins, yãnd y12, was examined in the mammalian brain. Concentrations of these two y subunits increased markedly, as did those of glial fibrillary acidic protein, during postnatal development in the rat cerebral cortex. In aged human brains, by contrast, the concentration of ytended to decrease with age, whereas that of 712 in the temporal cortex increased slightly. An immunohistochemical study of human brains revealed that 73 was abundant in the neuropil, whereas 712 was localized in glial cells. In the hippocampal formation of aged human brains, levels of y12-positive cells, as well as levels of glial fibrillary acidic protein-and vimentin-positive astrocytes, increased, in particular in the CAl subfield and the prosubiculum, in which there was a decrease in the number of pyramidal cells. The appearance of y12-positive cells associated with the loss of pyramidal cells was also observed in the hippocampus of rats that had been treated with kainic acid. These results indicate that 712 is strongly expressed in reactive astrocytes. In a study of cultured neural cells, we found that 712 was predominant in glioma cells, such as C6 and GA-i cells, in contrast with the specific localization of y~in PC12 pheochromocytoma cells, which are neuron-like cells. Taken together, the results indicate that y~and 712 are selectively expressed in neuronal and glial cells, respectively, and that concentrations of y~and 712 in the brain are related to the numbers and/or extent of maturation of these cells.

Mice with Deficiency of G Protein γ3 Are Lean and Have Seizures

“…Gng3 is predominantly expressed in the brain (1,5,17), where its expression increases during postnatal development (1,34). Within the brain, ␥ 3 is widely expressed in neurons rather than glial cells (2,22,33). In vitro RNA suppression studies predict a specific function for ␥ 3 in coupling various receptors to changes in calcium channel activity (9,25,26).…”

Gng12 is a novel negative regulator of LPS-induced inflammation in the microglial cell line BV-2

“…At the same time, the b and c complex can then regulate other effectors [14]. G proteins are comprised of three different subunits, a, b, and c, making them heterotrimeric.…”

Immunohistochemical localization of G protein βγ subunits in the lateral wall of the rat cochlea

“…By contrast, the γ subunits show greater divergence than the β subunits in their tissue‐specific distribution (Cali et al. 1992; Morishita et al. 1997).…”

“…Additionally, five β and 12 γ subunit genes have been identified in the human and mouse genomes (Watson et al. 1994; Morishita et al. 1997; Gautam et al.…”