Contribution of Atg1-dependent autophagy to TOR-mediated cell growth and survival.
The Ser/Thr kinase Atg1 (Ulk1/Unc51) appears to act as a convergence point for multiple signals that regulate autophagy, and in turn interacts with a large number of autophagy-related (Atg) proteins. Working in the Drosophila system, we recently found that overexpression of Atg1 is sufficient to induce autophagy, independent of upstream nutrient signals. We exploited this finding to examine the roles of autophagy in cell growth and death, and to test the interaction of Atg1 with the TOR signaling pathway. These studies provided genetic evidence that autophagy is a potent inhibitor of cell growth, and that high levels of autophagy lead to caspase-dependent apoptotic cell death in vivo. Atg1 also has an inhibitory effect on TOR signaling, indicating the existence of a positive feedback mechanism that may amplify the nutrient-dependent signals that control autophagy.
Neufeld
Thomas P
TP
Department of Genetics, Cell Biology and Development, University of Minnesota, Mineapolis, Minnesota 55455, USA. neufeld@med.umn.edu
D000818:Animals; D030801:Animals, Genetically Modified; D001343:Autophagy / Q000502:physiology*; D000071189:Autophagy-Related Protein-1 Homolog; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D017344:Genes, Insect; D008954:Models, Biological; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology*; D015398:Signal Transduction
D029721:Drosophila Proteins; D020794:Receptor Protein-Tyrosine Kinases; C080148:tor protein, Drosophila; C518074:Atg1 protein, Drosophila; D000071189:Autophagy-Related Protein-1 Homolog; D017346:Protein Serine-Threonine Kinases