Ras Induced Senescence 1 (RIS1)

Constitutive activation of the Ras pathway triggers an irreversible proliferation arrest reminiscent of replicative senescence. Transcription of this gene is upregulated in response to activation of the Ras pathway, but not under other conditions that induce senescence. RIS1 is similar to a rat cell surface receptor proposed to function in a neuronal survival pathway. RIS1 is not upregulated in association to any of the above-mentioned processes, but exclusively during Ras-senescence. Furthermore, RIS1 is also upregulated by the transcriptional factor Ets2, which is a known mediator of Ras-induced senescence. Interestingly, RIS1 is located at chromosomal position 3p21.3 and, more specifically, it is included in a short segment of just 1 Mb previously defined by other investigators for its tumor-suppressor activity.