Phosphatidylserine flipping enhances membrane curvature and negative charge required for vesicular transport.

Xu P, Baldridge RD, Chi RJ, Burd CG, Graham TR
J Cell Biol. 2013 202 (6): 875-86

PMID: 24019533 · PMCID: PMC3776346 · DOI:10.1083/jcb.201305094

Vesicle-mediated protein transport between organelles of the secretory and endocytic pathways is strongly influenced by the composition and organization of membrane lipids. In budding yeast, protein transport between the trans-Golgi network (TGN) and early endosome (EE) requires Drs2, a phospholipid translocase in the type IV P-type ATPase family. However, downstream effectors of Drs2 and specific phospholipid substrate requirements for protein transport in this pathway are unknown. Here, we show that the Arf GTPase-activating protein (ArfGAP) Gcs1 is a Drs2 effector that requires a variant of the ArfGAP lipid packing sensor (+ALPS) motif for localization to TGN/EE membranes. Drs2 increases membrane curvature and anionic phospholipid composition of the cytosolic leaflet, both of which are sensed by the +ALPS motif. Using mutant forms of Drs2 and the related protein Dnf1, which alter their ability to recognize phosphatidylserine, we show that translocation of this substrate to the cytosolic leaflet is essential for +ALPS binding and vesicular transport between the EE and the TGN.

MeSH Terms (20)

Adenosine Triphosphatases Amino Acid Motifs Amino Acid Sequence ATP-Binding Cassette Transporters Blotting, Western Calcium-Transporting ATPases Cell Membrane DNA-Binding Proteins Endosomes GTPase-Activating Proteins Immunoprecipitation Membrane Lipids Models, Molecular Molecular Sequence Data Phosphatidylserines Saccharomyces cerevisiae Saccharomyces cerevisiae Proteins Sequence Homology, Amino Acid trans-Golgi Network Transport Vesicles

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