Publication — IRIC

Tumor suppressor activity of the ERK/MAPK pathway by promoting selective protein degradation.

Constitutive activation of growth factor signaling pathways paradoxically triggers a cell cycle arrest known as cellular senescence. In primary cells expressing oncogenic ras, this mechanism effectively prevents cell transformation. Surprisingly, attenuation of ERK/MAP kinase signaling by genetic inactivation of Erk2, RNAi-mediated knockdown of ERK1 or ERK2, or MEK inhibitors prevented the activation of the senescence mechanism, allowing oncogenic ras to transform primary cells. Mechanistically, ERK-mediated senescence involved the proteasome-dependent degradation of proteins required for cell cycle progression, mitochondrial functions, cell migration, RNA metabolism, and cell signaling. This senescence-associated protein degradation (SAPD) was observed not only in cells expressing ectopic ras, but also in cells that senesced due to short telomeres. Individual RNAi-mediated inactivation of SAPD targets was sufficient to restore senescence in cells transformed by oncogenic ras or trigger senescence in normal cells. Conversely, the anti-senescence viral oncoproteins E1A, E6, and E7 prevented SAPD. In human prostate neoplasms, high levels of phosphorylated ERK were found in benign lesions, correlating with other senescence markers and low levels of STAT3, one of the SAPD targets. We thus identified a mechanism that links aberrant activation of growth signaling pathways and short telomeres to protein degradation and cellular senescence.

Date de publication
15 avril 2013
Chercheurs
Deschênes-Simard X, Gaumont-Leclerc MF, Bourdeau V, Lessard F, Moiseeva O, Forest V, Igelmann S, Mallette FA, Saba-El-Leil MK, Meloche S, Saad F, Mes-Masson AM, Ferbeyre G
Référence PubMed
Genes Dev. 2013;27(8):900-15
ID PubMed
23599344
Affiliation
Département de Biochimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada;