Protein turnover can be achieved via the lysosome/vacuole and the autophagic 
degradation pathways. Evidence has accumulated revealing that efficient 
autophagic degradation requires functional endosomal sorting complex required 
for transport (ESCRT) machinery. However, the interplay between the ESCRT 
machinery and the autophagy regulator remains unclear. Here, we show that FYVE 
domain protein required for endosomal sorting 1 (FREE1), a recently identified 
plant-specific ESCRT component essential for multivesicular body (MVB) 
biogenesis and plant growth, plays roles both in vacuolar protein transport and 
autophagic degradation. FREE1 also regulates vacuole biogenesis in both seeds 
and vegetative cells of Arabidopsis. Additionally, FREE1 interacts directly with 
a unique plant autophagy regulator SH3 domain-containing protein2 and associates 
with the PI3K complex, to regulate the autophagic degradation in plants. Thus, 
FREE1 plays multiple functional roles in vacuolar protein trafficking and 
organelle biogenesis as well as in autophagic degradation via a previously 
unidentified regulatory mechanism of cross-talk between the ESCRT machinery and 
autophagy process.