In this study the authors were able to identify how a protein called p62 is activated to induce autophagy. They found that p62 can be activated by reactive oxygen species (ROS). ROS are by-products of our metabolism that can cause damage in the cell. This ability of p62 to sense ROS allows the cell to remove the damage and to survive this stress. In lower organisms, such as fruit flies, p62 is not able to do this.
The team identified the part of the human p62 protein which allows it to sense ROS and created genetically modified fruit flies with ‘humanised’ p62. These ‘humanised’ flies survived longer in conditions of stress. Dr Korolchuk adds: “This tells us that abilities like sensing stress and activating protective processes like autophagy may have evolved to allow better stress resistance and a longer lifespan.”
Indeed, in the study, the authors found that specific mutations in human p62, which cause a neurodegenerative disease called amyotrophic lateral sclerosis (ALS), can prevent activation of p62 by ROS. These cells are then unable to induce protective autophagy, and the authors explain that this could underlie the premature death of neurons in patients with this devastating age-related disease.
In contrast, ‘humanised’ p62 fruit flies did not live longer suggesting that other mechanisms may be required. Paper. (public access) – Bernadette Carroll, Elsje G. Otten, Diego Manni, Rhoda Stefanatos, Fiona M. Menzies, Graham R. Smith, Diana Jurk, Niall Kenneth, Simon Wilkinson, Joao F. Passos, Johannes Attems, Elizabeth A. Veal, Elisa Teyssou, Danielle Seilhean, Stéphanie Millecamps, Eeva-Liisa Eskelinen, Agnieszka K. Bronowska, David C. Rubinsztein, Alberto Sanz, Viktor I. Korolchuk. Oxidation of SQSTM1/p62 mediates the link between redox state and protein homeostasis. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-017-02746-z More.
One wishes them well against ALS but it’s not clear that we did “evolve” to live longer. Was there a time when seventy to eighty years was not a normal human lifespan (granting that only recently have most people been able to achieve it)?
See also: Shock! Darwinism does not explain why old women exist It’s not clear, on reflection, that an evolutionary explanation for human female longevity is even needed. One difference between old women and old cows is that women are aware of death and can think of means of avoiding it. Such means might include establishing moral and legal rules against killing one’s parents and inheritance systems that give power to seniors over juniors.