MAPK and MEK Are Intracellular Signaling Proteins That Mediate Cell

MAPK and MEK are intracellular signaling proteins that mediate cell division induced by growth factors. When mutations in the normal MAPK and MEK genes result in an abnormally high level of MAPK and MEK activity and increases in the rate of cell division, then the mutated gene is called a(n)

A) spliceosome.
B) transposon.
C) tumor-suppressor gene.
D) oncogene.
E) None of the choices are correct.