Heterotrimeric GTP-binding proteins transduce receptor-mediated extracellular signals to their effectors. Several activated mutations of Gsα and Giα have been shown to be associated with endocrine tumors. In this report, we have evaluated the transforming activity of an putative activated form of Gα12 subunit. We found that transient expression in NIH3T3 cells of the Gα12 mutant with substitution of glutamine-229 for leucine could lead to focus formation and that stably transfected NIH3T3 cells could form colonies in soft agar and tumors in nude mice.
