Dynamin-2 promotes Atg9A retrieval from phagophores during autophagy.

Abstract

Autophagy involves the rapid growth of phagophores through membrane addition. This growth is triggered by vesicles containing the Atg9A protein. However, Atg9A is not incorporated into mature autophagosomes. We now demonstrate that Dynamin-2 (Dnm2) colocalizes with the BAR domain protein endophilin B1 (EndoB1/Bif-1/SH3GLB1) and other autophagy proteins when autophagy is induced. Our data suggest that Atg9A is retrieved from phagophores via fission, with help from Dnm2. Blocking Atg9A recycling, by mutating Dnm2, using RNA interference, or applying chemical inhibitors, causes Atg9A to remain in autophagosomes and be degraded during autophagy. Overall, these findings provide new insights into the roles of Dnm2 in autophagy.