Autophagy machinery in infected cell. An isolation membrane initially forms around the targeting viruses or macromolecules. It is considered that this isolation membrane originates from the endoplasmic reticulum (ER), and its formation is modulated by PI3K complex which is comprised of Vps34, p150, and Beclin-1. The elongation and closure of the autophagosomes are relevant to two ubiquitin-like systems: the Atg12-Atg5-Atg16L1 and LC3-II protein conjugations. After enwrapping the autophagic cargos, the autophagosome fuses with the lysosome, resulting in the acidification of autolysosome which is concomitant with degradation of the inner autophagosome membrane and the autophagosomal contents by lysosomal hydrolysis. The viral proteins of influenza A virus induce both positive and negative regulation of the autophagy pathway.
