title: Fission yeast autophagy induced by nitrogen starvation generates a nitrogen source that drives adaptation processes.
abstract: Autophagy is a conserved bulk protein degradation process that is proposed to play a role in events that arise when organisms are forced to radically change their fate, including nutritional starvation, differentiation and development. In our present study, we have identified fission yeast autophagy as a bulk protein degradation process induced by the deprivation of environmental nitrogen, the effects of which are known to trigger sexual differentiation as an adaptive response. Autophagy-defective mutants were found to be sterile in the absence of environmental nitrogen, but could complete sexual differentiation when nitrogen was supplied, suggesting that the major function of autophagy is to provide a nitrogen source. In addition, the environmental nitrogen levels act as an autophagy "on/off" switch, whereas components essential for sexual differentiation were dispensable for this regulation. We propose that fission yeast autophagy functions to supply nitrogen and is activated when cells cannot access exogenous nitrogen, thus ensuring that they can adapt and subsequently propagate.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Hongo, Tokyo 113-0033, Japan.
authors.forename: Toshiki A
authors.initials: TA
authors.lastname: Kohda
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tanaka
authors.forename: Mami
authors.initials: M
authors.lastname: Konomi
authors.forename: Mamiko
authors.initials: M
authors.lastname: Sato
authors.forename: Masako
authors.initials: M
authors.lastname: Osumi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D000222:Adaptation, Physiological; D001343:Autophagy; D015152:Blotting, Northern; D015153:Blotting, Western; D047468:Immunoprecipitation; D008854:Microscopy, Electron; D009584:Nitrogen / Q000378:metabolism*; D010766:Phosphorylation; D012568:Schizosaccharomyces / Q000378:metabolism / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism
chemical_list: D029702:Schizosaccharomyces pombe Proteins; D009584:Nitrogen