Divergent Roles of Autophagy in Virus Infection

Chiramel, Abhilash I.; Brady, Nathan R.; Bartenschlager, Ralf

Autophagy can operate either as a non-selective or a highly selective process: first, a starvation induced, non-selective pathway; second, a target-specific and selective autophagic pathway [10] . Non-selective or starvation-induced autophagy is thought to play an important role in supplying energy to the cell by the bulk degradation of proteins and organelles, whereas selective autophagy involves the recruitment of specific adaptor proteins such as p62, NBR1 (neighbor of BRCA1 gene 1), BNIP3 (BCL2 and adenovirus E1B 19 kDa-interacting protein 3) and NIX (NIP3-like protein X) that recognize ubiquitinated protein complexes and organelles, such as mitochondria (mitophagy), peroxisomes (pexophagy) and ribosomes (ribophagy), to target them to autophagosomes for degradation [10 12] . More recently, studies have shown that selective autophagy plays a crucial role in the elimination of pathogenic bacteria and viruses, termed xenophagy, thus extending the functions of autophagy to innate and adaptive immunity against pathogens [11] . Moreover, studies on selective autophagy have underlined the relevance of post-translational modifications, such as phosphorylation and ubiquitination, in linking autophagy adaptor protein function to autophagy substrate recognition [13, 14] . However, the role of adaptor proteins in non-selective autophagy still remains to be fully determined.