Identification of TMEM263 as an ER-resident protein that controls early stages of lipid droplet biogenesis.

TMEM263 (C12orf23) is an ER-resident protein with two transmembrane domains that is necessary and sufficient for lipid droplet formation and growth.

• Why it matters: Growth depends on sensing metabolic demand, yet the mechanistic link between growth control and early lipid droplet biogenesis remains unclear.
• What they did: TMEM263 was identified in a screen as ER-resident, and its alpha-hairpin transmembrane structure was tested for ER localization and lipid droplet accumulation; loss was examined in cells and zebrafish.
• The result: Loss of TMEM263 in cells and zebrafish significantly impairs lipid droplet accumulation, and in vivo loss is linked to organismal growth defects and proportional dwarfism.