RT Journal Article SR Electronic T1 The odd one out: Arabidopsis reticulon20 has a role in lipid biosynthesis JF bioRxiv FD Cold Spring Harbor Laboratory SP 123679 DO 10.1101/123679 A1 Verena Kriechbaumer A1 Lilly Maneta-Peyret A1 Stanley W Botchway A1 Jessica Upson A1 Louise Hughes A1 Jake Richardson A1 Maike Kittelmann A1 Patrick Moreau A1 Chris Hawes YR 2017 UL http://biorxiv.org/content/early/2017/04/07/123679.1.abstract AB 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.