A Ypt/Rab GTPase module makes a PAS.
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.
Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
Zhanna
Z
Lipatova
Nava
N
Segev
D001343:Autophagy; D002462:Cell Membrane / Q000201:enzymology; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D010588:Phagosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism*
D020662:Guanine Nucleotide Exchange Factors; D029701:Saccharomyces cerevisiae Proteins; C060755:YPT1 protein, S cerevisiae; D020691:rab GTP-Binding Proteins