Title : Characterization of the isolation membranes and the limiting membranes of autophagosomes in rat hepatocytes by lectin cytochemistry
Abstract :
- The isolation membranes and the limiting membranes of autophagosomes in rat hepatocytes were characterized by lectin cytochemistry using concanavalin A ( ConA ), Ricinus communis agglutinin 120 (RCA-120), and wheat germ agglutinin ( WGA )
- We found that RCA-120, ConA , and WGA bind to these membranes
- The distribution of the lectins on the isolation membranes was heterogeneous, mainly found on the rims, which we referred to as the peripheral dilated portion
- When the rims fused and thus formed autophagosomes the apparent sites of fusion were strongly labeled by the lectins
- After autophagosomes were transformed to autolysosomes by fusion with lysosomes, the limiting membranes became more densely and homogeneously labeled with the lectins
- We previously reported that cytochrome P-450 does not exist on the limiting membranes of the autophagosomes
- Taken together, these results suggest that the isolation membranes may originate not from endoplasmic reticulum membranes but from some post-Golgi membranes that contain complex type N and/or O-linked oligosaccharide chains