Anti-GNA13 (aa 183-212) polyclonal antibody

Specificity proteins (SPs) have pro-oncogenic functions in cancer cells, ranging from cancer cell proliferation, migration, invasion, and angiogenesis. There is strong evidence that several antineoplastic drugs target depletion of SP proteins via different pathways. However, the mode of action of SP3 and the underlying consequences of its depletion are not well understood. Here, we demonstrate that SP3 is overexpressed in invasive breast cancer cells vs normal counterparts. The gene expression analysis from The Cancer Genome Atlas datasets indicated that SP3 is strongly correlated with Akt signalling-related proteins, G protein subunit alpha 13, and RAB33B (RAB33B, member RAS oncogene family). RNA interference of SP3 decreased active phosphorylation of Akt at serine and threonine sites. These findings indicate that SP3 exhibits a pro-oncogenic function, which clearly fits the description of an nononcogene addiction gene. Future analyses are prompted to uncover the SP3 gene regulation function and to reveal downstream targets of SP3 in breast cancer.

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.