Bacterial AsmA Proteins Transfer Glycerophospholipids Between Membranes in Vitro

Gram-negative bacteria are surrounded by inner and outer membranes whose glycerophospholipid building blocks are synthesized in the inner membrane and redistributed to the outer membrane by poorly understood mechanisms. In eukaryotes, bridge-like lipid transfer proteins (BLTPs) transfer glycerophospholipids between membranes to support membrane homeostasis and biogenesis. Bacterial proteins in the AsmA family are related to BLTPs in structure and are proposed also to function in lipid transfer. Here we adapted a well-established in vitro lipid transfer assay to provide biochemical evidence that AsmA family proteins, TamB and YhdP, have the ability to transfer glycerophospholipids between membranes, supporting similar functions for AsmA proteins and BLTPs.