Figure 3. Targeting of intracellular bacteria for lysosomal destruction by xenophagy.
Top: Phagosomes mature constitutively and ultimately deliver their bacterial cargo to lysosomes. During LC3-assisted phagocytosis (LAP), conjugation of LC3/GABARAP to the limiting phagosomal membrane promotes phagosome maturation. Bottom: On damaged vacuoles, exposure of otherwise hidden glycans recruits the danger receptor galectin-8, whose accumulation provides an ‘eat-me’ signal for the cargo receptor NDP52, thereby induces autophagy. The ubiquitin-coat deposited by LRSAM1 and Parkin around cytosol-exposed bacteria (which may still be in association with vacuolar membrane remnants) serves as an alternative ‘eat-me’ signal for multiple cargo receptors (NDP52, Optn, p62), thereby inducing autophagy.