Nao Hosokawa

Cell biologist who, in Noboru Mizushima's lab, showed how mTORC1 directly holds the autophagy starter complex in check and helped discover the autophagy protein Atg101

Department of Physiology and Cell Biology, Tokyo Medical and Dental University (Noboru Mizushima lab, 2009, at the time of the study) · Department of Bioregulation and Metabolism, Tokyo Metropolitan Institute of Medical Science (2007)

Autophagy is the cell's recycling system: it wraps worn-out parts in a membrane and breaks them down for raw materials. Cells should only do this when food is short, so something has to keep autophagy off when nutrients are plentiful. In 2009, Nao Hosokawa, first author of the Atlas study HOS2009 from Noboru Mizushima's lab, showed in cultured cells how mTORC1, the cell's growth-control complex, does it. The autophagy starter kinase ULK1 sits in a large complex with Atg13 and FIP200. When nutrients are present, mTORC1 physically joins this complex and adds phosphate groups to ULK1 and Atg13, which keeps them inactive. Starvation or the drug rapamycin releases this brake, and autophagy begins. This gave a direct molecular link between nutrient sensing and autophagy.

In the same year Hosokawa was also first author of a paper in Autophagy that identified Atg101, a new mammalian protein that binds Atg13 and is needed for autophagy to proceed. An earlier first-author paper from 2007, at the Tokyo Metropolitan Institute of Medical Science and again with Mizushima, built mouse cell lines in which autophagy can be switched on and off with an antibiotic, and used them to show that autophagy helps cells shrink during starvation.

PubMed records under this name with autophagy work stop after 2009, and no later institutional page was found, so the affiliation shown is the one at the time of the study.

Milestones in the Atlas

A selection, not a full bibliography: only papers that meet the Atlas inclusion criteria.

Co-authors in the Atlas 2

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