ATG9A is a transmembrane autophagy related protein, that resides in basal conditions predominantly in the TGN and recycling endosomes. ATG9A has also been visualised at the plasma membrane, ER and mitochondria. Upon amino acid starvation, ATG9A vesicles traverse away from its perinuclear origin, and are proposed to traffic to subdomains of the ER, the omegasomes, for autophagosome biogenesis. The function of ATG9A in starvation-induced autophagy is enigmatic, but pivotal as autophagosome biogenesis is abrogated in KO cell lines. Theories of its function have been generated from experimental observations. One proposed function of ATG9A vesicles is to deliver necessary components for autophagosome biogenesis, such as membrane shaping proteins. ATG9A has also been suggested to be incorporated within the phagophore membrane to facilitate phagophore expansion as a lipid scramblase in collaboration with ATG2A, a lipid transfer protein. However, as a transmembrane protein that utilises the secretory and endocytic pathway to traverse the cell the exact pathway and vesicles that originate from these compartments have been difficult to decipher, in part due to its dynamic behavior. To explore this dynamic trafficking of ATG9A in cells, under amino acid starvation conditions I am developing novel approaches to visualise and probe the trafficking and function of ATG9A. Applying genetic codon expansion techniques, I plan to monitor the route of ATG9A to understand the donor and acceptor compartments, and to decipher ATG9As route to the phagophore and the machinery that controls this. Our hypothesis is that the identification of populations of ATG9A that originate from different organelles may reveal information about its function in autophagy.