Enhanced phospholipase C stimulation and transformation in NIH-3T3 cells expressing Q209LGq-alpha-subunits.
NIH-3T3 cells were transfected with cDNA encoding the native alpha-subunit of the G protein Gq(alpha q) or a mutant (Q209L) form of alpha q. Cells expressing Q209L-alpha q showed greatly enhanced basal phospholipase C activity. Stimulation of phospholipase C activity by prostaglandin F2 alpha or fetal calf serum was increased up to 10-fold in Q209L-alpha q-transfected cells. Continuous expression of Q209L-alpha q or overexpression of alpha q in NIH-3T3 cells resulted in formation of foci after 3 weeks. The number of foci was proportional to the number of transfected cells and was greater in cells expressing the Q209L-alpha q than in cells that overexpressed the wild type alpha q. Q209L-alpha q-transfected NIH-3T3 cells also formed colonies in soft agar indicating their capacity to grow in an anchorage-independent manner. Expression of Q209L-alpha q in Rat-1 cells resulted in enhanced basal and fetal calf serum-stimulated phospholipase C activity, but these cells were not transformed as assessed by either the focus formation or the soft agar colony formation assays. These results indicate that expression of continuously activated Gq-alpha can result in transformation in a cell type-specific manner.
De Vivo
M
M
Department of Pharmacology, Mount Sinai School of Medicine, City University of New York, New York 10029.
Chen
J
J
Codina
J
J
Iyengar
R
R
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D004247:DNA; D004789:Enzyme Activation; D005347:Fibroblasts; D019204:GTP-Binding Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D014162:Transfection; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*
D004247:DNA; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins