Abstract
Autophagy is the main eukaryotic degradation pathway for long-lived proteins, protein aggregates, and cytosolic organelles. Although the protein machinery involved in the biogenesis of autophagic vesicles is well described, very little is known about the mechanism of cytosolic transport of autophagosomes. In this study, we have identified an adaptor protein complex, formed by the two autophagic membrane-associated proteins LC3 and Rab7 and the novel FYVE and coiled-coil (CC) domain-containing protein FYCO1, that promotes microtubule (MT) plus end-directed transport of autophagic vesicles. We have characterized the LC3-, Rab7-, and phosphatidylinositol-3-phosphate-binding domains in FYCO1 and mapped part of the CC region essential for MT plus end-directed transport. We also propose a mechanism for selective autophagosomal membrane recruitment of FYCO1.