Nitrogen signaling factor triggers a respiration-like gene expression program in fission yeast.

Microbes have evolved intricate communication systems that enable individual cells of a population to send and receive signals in response to changes in their immediate environment. In the fission yeast Schizosaccharomyces pombe, the oxylipin nitrogen signaling factor (NSF) is part of such communication system, which functions to regulate the usage of different nitrogen sources. Yet, the pathways and mechanisms by which NSF acts are poorly understood. Here, we show that NSF physically interacts with the mitochondrial sulfide:quinone oxidoreductase Hmt2 and that it prompts a change from a fermentation- to a respiration-like gene expression program without any change in the carbon source. Our results suggest that NSF activity is not restricted to nitrogen metabolism alone and that it could function as a rheostat to prepare a population of S. pombe cells for an imminent shortage of their preferred nutrients. Synopsis: Chemical cell-to-cell communication in the fission yeast Schizosaccharomyces pombe is essential for adaption to environmental changes in nutrient availability. This study uncovers that the extracellular signaling molecule nitrogen signaling factor (NSF) functions to counter nitrogen catabolite repression, and to switch from fermentation to respiratory metabolism. Nitrogen Signaling Factor (NSF) functions in an intra-species communication system of. With increasing cell density during population growth, NSF reaches a critical concentration that triggers a switch from a fermentation- to a respiration-like gene expression program. The putative 1-acyldihydroxyacetone phosphate reductase Ayr1 counteracts NSF signaling. The mitochondrial sulfide:quinone oxidoreductase Hmt2 is a direct and functionally relevant target of NSF. NSF is a transmissible signal that activates mitochondrial respiration to maximize growth. The oxylipin NSF is a transmissible signal that activates mitochondrial respiration to maximize growth. [ABSTRACT FROM AUTHOR]