Crosstalk between JNK and SUMO signaling pathways: deSUMOylation is protective against H2O2-induced cell injury

Background

Oxidative stress is a key feature in the pathogenesis of several neurological disorders. Following oxidative stress stimuli a wide range of pathways are activated and contribute to cellular death. The mechanism that couples c-Jun N-terminal kinase (JNK) signaling, a key pathway in stress conditions, to the small ubiquitin-related modifier (SUMO), an emerging protein in the field, is largely unknown.

Methodology/Principal Findings

With this study we investigated if SUMOylation participates in the regulation of JNK activation as well as cellular death in a model of H₂O₂ induced-oxidative stress. Our data show that H₂O₂ modulates JNK activation and induces cellular death in neuroblastoma SH-SY5Y cells. Inhibition of JNK''s action with the D-JNKI1 peptide rescued cells from death. Following H₂O₂, SUMO-1 over-expression increased phosphorylation of JNK and exacerbated cell death, although only in conditions of mild oxidative stress. Furthermore inhibition of SUMOylation, following transfection with SENP1, interfered with JNK activation and rescued cells from H₂O₂ induced death. Importantly, in our model, direct interaction between these proteins can occur.

Conclusions/Significance

Taken together our results show that SUMOylation may significantly contribute to modulation of JNK activation and contribute to cell death in oxidative stress conditions.