Activation of a Ras protein Inactive Ras protein (left) is activated by a GEF protein opening the binding site allowing GDP to exit. Afterwards GTP can bind to RAS turning it into the active form (right). Ras proteins are involved in transmitting signals within cells turning on genes involved in cell growth, differentiation and survival. Mutations in ras genes can lead to permanently activated proteins causing cells to subdivide without control. nucleotide stock pictures, royalty-free photos & images