Linear ubiquitin as a common regulator of cellular stress.

Linear or M1-ubiquitination (Ub) is required for optimal NF-kB activation and for cell death inhibition. Using Drosophila as a model organism, Aalto et al. found that hypoxia, oxidative and mechanical stress induced M1-Ub by the HOIP homolog, LUBEL. Increased M1-Ub had a protective function driven by activation of the NF-κB transcription factor Relish via the Immune deficiency pathway (Imd). This protective M1-Ub was also induced upon cellular stress in colorectal cancer cells. Collectively, they propose that M1-Ub is a conserved, common response to different forms of stresses. These findings may have important implications for the use of HOIP inhibitors for cancer treatment. Comment on: https://doi.org/10.1111/febs.16425.