Inactive (left) and active (right) Ras proteins, illustration. Inactive Ras proteins have GDP (guanine diphosphate, orange) bound to their active site, while active Ras proteins have GTP (guanine triphosphate, orange) bound to their active site. 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, often leading to cancer. |