During autophagy, double-membrane autophagosomes deliver sequestered cytoplasmic content
to late endosomes and lysosomes for degradation. The molecular mechanism of autophagosome
maturation is still poorly characterized. The small GTPase Rab11 regulates endosomal
traffic, and is thought to function at the level of recycling endosomes. Here we show
that loss of Rab11 leads to accumulation of autophagosomes and late endosomes in Drosophila
melanogaster. Rab11 translocates from recycling endosomes to autophagosomes in response
to autophagy induction, and physically interacts with Hook, a negative regulator of
endosome maturation. Hook anchors endosomes to microtubules, and we show that Rab11
facilitates the fusion of endosomes and autophagosomes by removing Hook from mature
late endosomes and inhibiting its homodimerization. Thus, induction of autophagy appears
to promote autophagic flux by increased convergence with the endosomal pathway.
