Autophagosomes and Cvt vesicles are limited by two membrane layers. The biogenesis of these unconventional vesicles and the origin of their membranes is hardly understood. We here identify in S. cerevisiae Trs85, a non-essential component of the TRAPP complexes to be required for the biogenesis of Cvt vesicles. The TRAPP complexes function in ER-to-Golgi and Golgi trafficking. Growing trs85 cells show a defect in the organization of the preautophagosomal structure. While proaminopeptidase I is normally recruited to the preautophagosomal structure, the recruitment of GFP-Atg8 depends on Trs85. Autophagy proceeds in the absence of Trs85, albeit at a reduced rate. Our electron microscopic analysis demonstrate that the reduced autophagic rate of trs85 cells does not result from a reduced size of the autophagosomes. Growing and starved cells lacking Trs85 did not show defects in vacuolar biogenesis, mature vacuolar proteinase B and carboxypeptidase Y were present. Also vacuolar acidification was normal in these cells. It is known that mutations impairing the integrity of the ER or Golgi block both autophagy and the Cvt pathway. But the phenotypes of trs85 cells show striking differences to those seen in mutants with defects in the early secretory pathway. This suggests that Trs85 might play a direct role in the Cvt pathway and autophagy.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|