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Figure 1.
Conservation of the process of autophagic removal of mitochondria and intracellular bacteria
The process involves an autophagic adapter (e.g., p62, NDP52 [nuclear dot protein 52], or Nix), and a mammalian Atg8 paralog (LC3, Gabarap) that binds to the adapter via a WXXL motif, thus bringing the targeted cargo (mitochondria, bacteria) into the nascent autophagic organelle, termed the phagophore; the phagophore grows, wraps around the target, and eventually closes, leading to sequestration and elimination. (A) Mitochondria in mammalian cells are removed by autophagy via the Nix adapter (also known as BNIP3L) during developmental elimination of mitochondria, or via ubiquitination of VDAC1 (voltage-dependent anion channel 1; see text) recognized by the adapter p62 for removal of stressed (e.g., depolarized or damaged) mitochondria. (B) Intracellular bacteria exposed to the cytosol are decorated by ubiquitin (Ub) and recognized by autophagic adapters (p62 or NDP52) for sequestration into autophagosomes and elimination. |
