Bif-1 regulates Atg9 trafficking by mediating the fission of Golgi membranes during autophagy.

Atg9 is a transmembrane protein essential for autophagy which cycles between the Golgi network, late endosomes and LC3-positive autophagosomes in mammalian cells during starvation through a mechanism that is dependent on ULK1 and requires the activity of the class III phosphatidylinositol-3-kinase (PI3KC3). In this study, we demonstrate that the N-BAR-containing ...
protein, Bif-1, is required for Atg9 trafficking and the fission of Golgi membranes during the induction of autophagy. Upon starvation, Atg9-positive membranes undergo continuous tubulation and fragmentation to produce cytoplasmic punctate structures that are positive for Rab5, Atg16L and LC3. Loss of Bif-1 or inhibition of the PI3KC3 complex II suppresses starvation-induced fission of Golgi membranes and peripheral cytoplasmic redistribution of Atg9. Moreover, Bif-1 mutants, which lack the functional regions of the N-BAR domain that are responsible for membrane binding and/or bending activity, fail to restore the fission of Golgi membranes as well as the formation of Atg9 foci and autophagosomes in Bif-1-deficient cells starved of nutrients. Taken together, these findings suggest that Bif-1 acts as a critical regulator of Atg9 puncta formation presumably by mediating Golgi fission for autophagosome biogenesis during starvation.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Animals, Autophagy, Autophagy-Related Proteins, Golgi Apparatus, HeLa Cells, Humans, Intracellular Membranes, Membrane Proteins, Mice, Phagosomes, Phosphatidylinositol 3-Kinases, Protein Structure, Tertiary, Protein Transport
Autophagy
Date: Jan. 01, 2011
Download Curated Data For This Publication
222075
Switch View:
  • Interactions 2