The BioGRID | PUBLICATION VIEW

	Mol. Cell Jul (2005); 19(1):15-26
The TOR and EGO protein complexes orchestrate microautophagy in yeast.
Dubouloz F, Deloche O, Wanke V, Cameroni E, De Virgilio C
Department of Microbiology and Molecular Medicine, University of Geneva Medical School, 1211 Geneva 4, Switzerland.
Abstract: The rapamycin-sensitive TOR signaling pathway in Saccharomyces cerevisiae positively controls cell growth in response to nutrient availability. Accordingly, TOR depletion or rapamycin treatment causes regulated entry of cells into a quiescent growth phase. Although this process has been elucidated in considerable detail, the transition from quiescence back to proliferation is poorly understood. Here, we describe the identification of a conserved member of the RagA subfamily of Ras-related GTPases, Gtr2, which acts in a vacuolar membrane-associated protein complex together with Ego1 and Ego3 to ensure proper exit from rapamycin-induced growth arrest. We demonstrate that the EGO complex, in conjunction with TOR, positively regulates microautophagy, thus counterbalancing the massive rapamycin-induced, macroautophagy-mediated membrane influx toward the vacuolar membrane. Moreover, large-scale genetic analyses of the EGO complex confirm the existence of a growth control mechanism originating at the vacuolar membrane and pinpoint the amino acid glutamine as a key metabolite in TOR signaling.
[PUBMED: 15989961]