A Ypt/Rab GTPase module makes a PAS

Autophagy. 2012 Aug;8(8):1271-2. doi: 10.4161/auto.20872. Epub 2012 Jun 6.

Abstract

Organization of membrane micro-domains by Ypt/Rab GTPases is key for all membrane trafficking events in eukaryotic cells. Since autophagy is a membrane trafficking process, it was expected that these GTPases would play a role in autophagy as well. While evidence about participation of Ypt/Rabs in autophagy is beginning to emerge, the mechanisms by which they act in this process are still not clear. Moreover, it is still questionable if and how Ypt/Rabs coordinate autophagy with other cellular trafficking processes. Yeast Ypt1 and its mammalian homolog Rab1 are required for both endoplasmic reticulum (ER)-to-Golgi transport and autophagy, suggesting that they coordinate these two processes. In our recent paper, we identify Atg11, a bona fide phagophore assembly site (PAS) component, as a downstream effector of Ypt1. Moreover, we show that three components of a GTPase module--the Ypt1 activator, Trs85-containing TRAPP complex, Ypt1, and the Atg11 effector--interact on the PAS and are required for PAS formation during selective autophagy. We propose that Ypt/Rabs coordinate the secretory and the autophagic pathways by recruiting process-specific effectors.

MeSH terms

  • Autophagy
  • Cell Membrane / enzymology
  • Guanine Nucleotide Exchange Factors / metabolism
  • Humans
  • Models, Biological
  • Phagosomes / metabolism*
  • Saccharomyces cerevisiae / cytology*
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • rab GTP-Binding Proteins / metabolism*

Substances

  • Guanine Nucleotide Exchange Factors
  • Saccharomyces cerevisiae Proteins
  • YPT1 protein, S cerevisiae
  • rab GTP-Binding Proteins