IHEM   20887
INSTITUTO DE HISTOLOGIA Y EMBRIOLOGIA DE MENDOZA DR. MARIO H. BURGOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Molecular machinery required for fusion of autophagosomes and endocytic compartments.
Autor/es:
COLOMBO, M. I.
Lugar:
Ventura, California, USA
Reunión:
Conferencia; Gordon Research Conference on Autophagy in Stress, Development, and Disease; 2008
Resumen:
Morphological and biochemical studies have shown that autophagosomes fuse with endosomes forming the so called amphisomes, a prelysosomal hybrid organelle. We have analyzed at the molecular level the interaction of MVBs with the autophagic pathway in K562 cells overexpressing GFP-Rab11 (MVBs marker) and the autophagosomal protein RFP-LC3. Autophagy inducers such as starvation or rapamycin caused an enlargement of the vacuoles decorated with GFP-Rab11 and a remarkable colocalization with LC3. This convergence was abrogated by a Rab11 dominant negative mutant, indicating that a functional Rab11 is involved in the interaction between MVBs and the autophagic pathway. Fusion of MVBs and autophagosomes in living cells was visualized by confocal microscopy. Interestingly, autophagy induction caused calcium accumulation in LC3-labeled compartments. Furthermore, the convergence between the endosomal and autophagic pathways was attenuated by the Ca2+ chelator BAPTA-AM indicating that fusion of MVBs with the autophagosome compartment is a calcium-dependent event.