ATG2A interacts with RAB1A and ARFGAP1 positive membranes during autophagosome biogenesis

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Abstract
Autophagosomes form from seed membranes that expand through bulk-lipid transport via the bridge-like lipid transporter ATG2. The origins of the seed membranes and their relationship to the lipid transport machinery are poorly understood. Using proximity labeling and a variety of fluorescence microscopy techniques, we show that ATG2A localizes to extra-Golgi ARFGAP1 puncta during autophagosome biogenesis. ARFGAP1 itself is dispensable during macroautophagy, but among other proteins associating to these membranes, we find that RAB1 is essential. ATG2A co-immunoprecipitates strongly, albeit indirectly, with RAB1A, and siRNA-mediated depletion of RAB1A/B blocks autophagy downstream of LC3B lipidation, similar to ATG2A depletion. Further, when either autophagosome formation or the early secretory pathway is perturbed, ARFGAP1 and RAB1A accumulate at ectopic locations with autophagic machinery. Our results indicate that ATG2A engages a RAB1A complex on select early secretory membranes in support of autophagosome biogenesis.
Funding Information
  • HHS | National Institutes of Health (R01 GM100930)
  • HHS | National Institutes of Health (R35 GM153482)
  • HHS | National Institutes of Health (R01 GM151829)
  • HHS | National Institutes of Health (DA018343)
  • HHS | National Institutes of Health (F31 AG079606)
  • HHS | National Institutes of Health (F31 DK136246)
  • Aligning Science Across Parkinson's (ASAP-025173)
  • Howard Hughes Medical Institute
  • Human Frontier Science Program (10.52044/HFSP.LT0000562020-C.pc.gr.165136)
  • Wellcome Leap

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