Mouse TSPO in a lipid environment interacting with a functionalized monolayer

► Oligomeric structure of mammalian TSPO in membrane under functionalized monolayer. ► Low detergent over TSPO ratio preserves monolayer structure. ► His-tagged TSPO appears like “donuts” adsorbed under Ni-NTA functionalized monolayer. ► Electron microscopy image analysis suggests that mouse TSPO might form a tetramer. ► Bacterial and mammalian TSPO with high homologue sequences form different polymers.