Small GTPase proteins in macroautophagy

Figures & data

Figure 1. Current model for the reciprocal roles of Arl1 and Ypt6 in macroautophagy. Data shown in ref. 8 demonstrate that Arl1 and Ypt6 in S. cerevisiae function to deliver Atg9-containing vesicles from the Golgi apparatus to the growing phagophore at the phagophore assembly site (PAS) to make the autophagosome by virtue of their interactions with the Golgi-associated retromer complex (GARP). In mutants lacking either ARL1 or YPT6, autophagy proceeds normally at the permissive temperature of 30°C because one of the 2 proteins is sufficient to bind to the GARP comples. However, in mutants lacking either of the genes, autophagy is inhibited at the restrictive temperature of 37°C presumably because the strength of the interaction with a single small GTPase is insufficient to retain GARP on the membrane at this temperature. A conditional mutant lacking both small GTPases is unable to perform autophagy at the permissive temperature.

Yang S, Rosenwald AG. Autophagy in Saccharomyces cerevisiae requires the monomeric GTP-binding proteins, Arl1 and Ypt6. Autophagy 2016; 12(10):1-17; https://doi.org/10.1080/15548627.2016.1196316

 PubMed Web of Science ®Google Scholar