title: The Atg1-Tor pathway regulates yolk catabolism in Drosophila embryos.
abstract: Yolk provides an important source of nutrients during the early development of oviparous organisms. It is composed mainly of vitellogenin proteins packed into membrane-bound compartments called yolk platelets. Catabolism of yolk is initiated by acidification of the yolk platelet, leading to the activation of Cathepsin-like proteinases, but it is unknown how this process is triggered. Yolk catabolism initiates at cellularization in Drosophila melanogaster embryos. Using maternal shRNA technology we found that yolk catabolism depends on the Tor pathway and on the autophagy-initiating kinase Atg1. Whereas Atg1 was required for a burst of spatially regulated autophagy during late cellularization, autophagy was not required for initiating yolk catabolism. We propose that the conserved Tor metabolic sensing pathway regulates yolk catabolism, similar to Tor-dependent metabolic regulation on the lysosome.
authors.affiliation: Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Hallie
authors.initials: H
authors.lastname: Kuhn
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Richelle
authors.initials: R
authors.lastname: Sopko
authors.affiliation: Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Margaret
authors.initials: M
authors.lastname: Coughlin
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, MA 02115, USA Howard Hughes Medical Institute, Boston, MA 02115, USA.
authors.forename: Norbert
authors.initials: N
authors.lastname: Perrimon
authors.affiliation: Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA timothy_mitchison@hms.harvard.edu.
authors.forename: Tim
authors.initials: T
authors.lastname: Mitchison
mesh_terms: D000818:Animals; D000071189:Autophagy-Related Protein-1 Homolog; D015153:Blotting, Western; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins / Q000378:metabolism*; D004530:Egg Yolk / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D008854:Microscopy, Electron; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D012394:Rosaniline Dyes; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D012394:Rosaniline Dyes; C048139:Coomassie blue; C416303:target of rapamycin protein, Drosophila; C518074:Atg1 protein, Drosophila; D000071189:Autophagy-Related Protein-1 Homolog; D017346:Protein Serine-Threonine Kinases; D058570:TOR Serine-Threonine Kinases
keywords: Drosophila; Tor; Yolk