Rapalink-1 reveals TOR-dependent genes and an agmatinergic axis-based metabolic feedback regulating TOR activity and lifespan in fission yeast.

Abstract

The Target of Rapamycin, TOR, is a conserved signalling pathway with characterised chemical inhibitors such as rapamycin and torin1. Bi-steric third-generation inhibitors, such as rapalink-1 have been developed, however, their effects on organismal gene expression and lifespan have not been characterised. Here, we demonstrate that rapalink-1 affects fission yeast spatial and temporal growth and prolongs chronological lifespan with a distinct TORC1 selectivity profile. Endosome and vesicle-mediated transport and homeostasis processes related to autophagy render cells resistant to rapalink-1. Our study reveals TOR-regulated genes with unknown roles in ageing, including all fission yeast agmatinases, the enzymes that convert agmatine to putrescine and urea. Through genome-wide screens, we identify sensitive and resistant mutants to agmatine and putrescine. Genetic interactome assays for the agmatinase agm1 and further cell and molecular analyses demonstrate that impairing the agmatinergic branch of arginine catabolism results in TOR activity levels that are beneficial for growth but detrimental for chronological ageing. Our study reveals the anti-ageing action of agmatinases within a metabolic circuit that regulates TOR activity, protein translation levels and lifespan.