2,2′-bis(monoacylglycero) PO₄ (BMP), but not 3,1′-BMP, increases membrane curvature stress to enhance α-tocopherol transfer protein binding to membranes

Previous work revealed that α-tocopherol transfer protein (α-TTP) co-localizes with bis(monoacylglycero)phosphate (BMP) in late endosomes. BMP is a lipid unique to late endosomes and is believed to induce membrane curvature and support the multivesicular nature of this organelle. We examined the effect of BMP on α-TTP binding to membranes using dual polarization interferometry and vesicle-binding assay. α-TTP binding to membranes is increased by the curvature-inducing lipid BMP. α-TTP binds to membranes with greater affinity when they contain the 2,2′-BMP versus 3,1′-BMP isomers.