TY - JOUR T1 - The odd one out: <em>Arabidopsis</em> reticulon20 has a role in lipid biosynthesis JF - bioRxiv DO - 10.1101/123679 SP - 123679 AU - Verena Kriechbaumer AU - Lilly Maneta-Peyret AU - Stanley W Botchway AU - Jessica Upson AU - Louise Hughes AU - Jake Richardson AU - Maike Kittelmann AU - Patrick Moreau AU - Chris Hawes Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/04/07/123679.1.abstract N2 - The family of reticulon proteins has been shown to be involved in a variety of functions in eukaryotic cells including tubulation of the endoplasmic reticulum (ER), formation of cell plates and primary plasmodesmata. Reticulons are integral ER membrane proteins characterised by a reticulon homology domain comprising four transmembrane domains which results in the reticulons sitting in the membrane in a W-topology. Here we report on a subgroup of reticulons with an extended N-terminal domain and in particular on arabidopsis reticulon 20. We show that reticulon 20 is located in a unique punctate pattern on the ER membrane. Its closest homologue reticulon 19 labels the whole ER. We show that mutants in RTN20 or RTN19, respectively, display a significant change in sterol composition in the roots indicating a role in lipid biosynthesis or regulation. A third homologue in this family - 3BETAHSD/D1- is localised to ER exit sites resulting in an intriguing location difference for the three proteins. ER -