Figure 1.

Pro- and antiapoptotic Ras and Rheb signaling based on different effectors and cellular context. Growth factors and insulin lead to the activation of Ras or Rheb GTPase, via their specific receptors. Downstream of activated Ras, a pleiotropy of downstream targets (i.e., PI3K, Raf. Ral Gef, Rassf1/5) are activated that, cooperatively, contribute to the overall cellular signaling outcome. Activated Rheb, however, stimulates the mTor pathway, leading to either pro- or antiapoptotic signaling, which critically depends on the cellular context. For details see text.