Ras and p53: An unsuspected liaison

Abstract

The precise mechanism by which Ras proteins mediate mitogenic signaling remains obscure. We have identified the p53/p21Cip1 axis as an essential component of the Ras mitogenic pathway. Moreover, cells carrying an inactive p53/p21Cip1/Rb pathway sustain cell proliferation by inducing retroactivation of the MAPK signaling cascade in a Ras-independent manner.