InterPro domain: IPR018939

Autophagy is a degradative transport pathway that delivers cytosolic proteins to the lysosome (vacuole) [ 1 ] and is induced by starvation [ 2 ]. Cytosolic proteins appear inside the vacuole enclosed in autophagic vesicles. Autophagy significantly differs from other transport pathways by using double membrane layered transport intermediates, called autophagosomes [ 3 , 4 ]. The breakdown of vesicular transport intermediates is a unique feature of autophagy [ 5 ]. Autophagy can also function in the elimination of invading bacteria and antigens [ 5 ].

There are more than 25 AuTophaGy-related (ATG) genes that are essential for autophagy, although it is still not known how the autophagosome is made. Atg9 is a potential membrane carrier to deliver lipids that are used to form the vesicle. Atg27 is another transmembrane protein, and is a cycling protein [ 5 ].

It acts as an effector of VPS34 phosphatidylinositol 3-phosphate kinase signalling and regulates the cytoplasm to vacuole transport (Cvt) vesicle formation. It is also required for autophagy-dependent cycling of ATG9.

1. The breakdown of autophagic vesicles inside the vacuole depends on Aut4p. J. Cell. Sci. 113 ( Pt 22), 4025-33
2. AUT3, a serine/threonine kinase gene, is essential for autophagocytosis in Saccharomyces cerevisiae. J. Bacteriol. 179, 3875-83
3. A genomic screen identifies AUT8 as a novel gene essential for autophagy in the yeast Saccharomyces cerevisiae. Gene 274, 151-6
4. Toward unraveling membrane biogenesis in mammalian autophagy. Curr. Opin. Cell Biol. 20, 401-7
5. Atg27 is a second transmembrane cycling protein. Autophagy 3, 254-6