Autophagy is a conserved catabolic process that degrades the cell’s own components through the lysosomal machinery in response to cell stress. Atg6/beclin 1 is a core component of the mammalian vacuolar protein sorting 34 (Vps34) complex that is required for autophagy. It is also a tumour suppressor, a function that has been attributed to its role in autophagy. But could the potential function of Atg6/beclin 1 in other vesicle trafficking pathways be involved in tumour development? On , Eric Baehrecke and co-workers generate Atg6 mutant Drosophila and show that Atg6 is essential for autophagy, endocytosis and protein secretion. By contrast, the core autophagy gene Atg1 is required for autophagy and protein secretion only. Consistent with the tumour suppressor role of beclin 1, loss of Atg6 causes over-production of blood cells and the formation of melanotic blood cell masses. Together, these results suggest that the involvement of Atg6/beclin 1 in multiple vesicle trafficking pathways underlies its role as a tumour suppressor.
