Rabbit Anti-Human GNA12 (a.a. 113-172) Polyclonal antibody

Diffuse brain invasion is a major reason for poor prognosis of glioma patients. The molecular mechanisms underlying infiltration are different from those of other cancer types. To detect genes associated with glioma invasion, highly migratory clones were selected from U373MG glioma cells and from primary glioblastoma cells, and the gene expression pattern of these "fast" cells was compared with that of the original ("slow") cells using oligonucleofide microarrays comprising 12,625 genes. A total of 28 genes were differently expressed in both primary and established cell populations, including 19 genes that were upregulated and 9 that were downregulated in fast cells. Most of these genes have not been linked to glioma invasion so far. Specifically, differentially expressed genes included those encoding extracellular matrix components (COL16A1, DPT), proteases (CATD, PRSS11), cytokines (MDK, IL-8), transport proteins (SLCIA3, ATP10B), cytoskeleton constituents (ACTA2, ACTSG, NEFL), DNA repair enzymes (WRN, ADPRTL2), and G-protein signaling components (GNA12, RGS3, RGS4). RGS3 and RGS4, which are homologs of the Drosophila glia gene loco, were further functionally analyzed. U373MG glioma cell clones overexpressing RGS3 or RGS4 showed an increase of both adhesion and migration. These findings expand the spectrum of possible molecular pathways underlying the invasion of neoplastic astrocytes. Specifically, they suggest that RGS proteins and G-protein-mediated signal transduction are evolutionary conserved functional players.

G protein?coupled receptor signaling is required for the navigation of immune cells along chemoattractant gradients. However, chemoattractant receptors may couple to more than one type of heterotrimeric G protein, each of which consists of a G?, G?, and G? subunit, making it difficult to delineate the critical signaling pathways. Here, we used knockout mouse models and time-lapse microscopy to elucidate G? and G? subunits contributing to complement C5a receptor-mediated chemotaxis. Complement C5a-mediated chemokinesis and chemotaxis were almost completely abolished in macrophages lacking Gnai2 (encoding G?(i2)), consistent with a reduced leukocyte recruitment previously observed in Gnai2(?/?) mice, whereas cells lacking Gnai3 (G?(i3)) exhibited only a slight decrease in cell velocity. Surprisingly, C5a-induced Ca2+ transients and lamellipodial membrane spreading were persistent in Gnai2(?/?) macrophages. Macrophages lacking both Gnaq (G?(q)) and Gna11 (G?(11)) or both Gna12 (G?(12)) and Gna13 (G?(13)) had essentially normal chemotaxis, Ca2+ signaling, and cell spreading, except Gna12/Gna13-deficient macrophages had increased cell velocity and elongated trailing ends. Moreover, Gnaq/Gna11-deficient cells did not respond to purinergic receptor P2Y(2) stimulation. Genetic deletion of Gna15 (G?(15)) virtually abolished C5a-induced Ca2+ transients, but chemotaxis and cell spreading were preserved. Homozygous Gnb1 (G?(1)) deletion was lethal, but mice lacking Gnb2 (G?(2)) were viable. Gnb2(?/?) macrophages exhibited robust Ca2+ transients and cell spreading, albeit decreased cell velocity and impaired chemotaxis. In summary, complement C5a-mediated chemotaxis requires G?(i2) and G?(2), but not Ca2+ signaling, and membrane protrusive activity is promoted by G proteins that deplete phosphatidylinositol 4,5-bisphosphate.