Enhanced phospholipase C stimulation and transformation in NIH-3T3 cells expressing Q209LGq-alpha-subunits

J Biol Chem. 1992 Sep 15;267(26):18263-6.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3T3 Cells
  • Animals
  • Base Sequence
  • Blotting, Western
  • DNA
  • Enzyme Activation
  • Fibroblasts
  • GTP-Binding Proteins / genetics*
  • Mice
  • Molecular Sequence Data
  • Mutation
  • Transfection
  • Type C Phospholipases / genetics
  • Type C Phospholipases / metabolism*


  • DNA
  • Type C Phospholipases
  • GTP-Binding Proteins