Autophagy regulation through Atg9 traffic
Rapid membrane expansion is the key to autophagosome formation during nutrient starvation. In this issue, Yamamoto et al. (2012. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201202061) now provide a mechanism for vesicle-mediated initiation of autophagosome biogenesis. They show that Atg9 vesicles, produced de novo during starvation, are ∼30-60 nm in size and contain ∼30 molecules of Atg9. These vesicles assemble to form an autophagosome, and subsequently, the Atg9 embedded in the outer membrane is recycled to avoid degradation.