No abstract

Autophagy can degrade cargos with the help of selective autophagy receptors such as p62/SQSTM1, which facilitates the degradation of ubiquitinated cargo. While the process of autophagy has been linked to aging, the impact of selective autophagy in lifespan regulation remains unclear. We have recently shown in Caenorhabditis elegans that transcript levels of sqst-1/p62 increase upon a hormetic heat shock, suggesting a role of SQST-1/p62 in stress response and aging. Here, we find that sqst-1/p62 is required for hormetic benefits of heat shock, including longevity, improved neuronal proteostasis, and autophagy induction. Furthermore, overexpression of SQST-1/p62 is sufficient to induce autophagy in distinct tissues, extend lifespan, and improve the fitness of mutants with defects in proteostasis in an autophagy-dependent manner. Collectively, these findings illustrate that increased expression of a selective autophagy receptor is sufficient to induce autophagy, enhance proteostasis and extend longevity, and demonstrate an important role for sqst-1/p62 in proteotoxic stress responses.

Heterotrophic production and abundance of prokaryotes (i.e., Bacteria and Archaea) in meso-(200-1000 m) and bathypelagic (. 1000 m) zones were measured at 31 stations along meridional transects of the central Pacific and Pacific sector of the Southern Ocean, covering a latitudinal range from 67.5uS to 53.6uN. Prokaryotic production and biomass in the mesopelagic zone displayed strong regional variation, generally consistent with model-based estimates of sinking particulate organic carbon (POC) flux patterns. In the bathypelagic zone, the prokaryotic abundance distributions reflected sinking POC flux patterns, whereas the prokaryotic production distributions were complex and unrelated to sinking POC fluxes. In general, the prokaryotic carbon consumption (PCC) was accounted for by the POC flux, within a factor of three, except in the bathypelagic zone of the subtropical region, where PCC exceeded the POC flux at 1000 m by up to seven times. Our results generally support the notion that prokaryote abundance and production distributions in the ocean's interior display consistent vertical patterns among distant locations and generally reflect the POC flux regime over a large scale, although complex prokaryotic production distributions in the bathypelagic zone might indicate the presence of links between regional hydrographic features and organic carbon delivery in deep waters.