Fig 1. Choline transporter CTL1 locates at the trans-Golgi network (TGN), a post-Golgi compartment acting as a central hub in the cell where endosomal plasma membrane recycling takes place as well as secretory sorting to plasma membrane and trafficking to late endosomes.

CTL1 is involved in phosphatidylcholine (PC) membrane homeostasis, probably by creating a gradient of choline on either side of TGN membranes. Two studies published in this issue of PLOS Biology show that TGN sorting of plasmodesmata callose-binding proteins (PDCBs), the ion transporter NRAMP1, and the auxin carrier PIN1, which polarly localised at the basal plasma membrane, depends on choline-mediated lipid homeostasis. Abbreviations: PA, phosphatidic acid.