Phospholipid transfer protein is one of at least two lipid transfer proteins found in human plasma. The encoded protein transfers phospholipids from triglyceride-rich lipoproteins to high density lipoprotein (HDL). In addition to regulating the size of HDL particles, this protein may be involved in cholesterol metabolism. At least two transcript variants encoding different isoforms have been found for this gene.

Human plasma contains at least 2 different lipid transfer proteins: cholesteryl ester transfer protein , also referred to as lipid transfer protein I, and phospholipid transfer protein (PLTP), also referred to as lipid transfer protein II. It appeared that the PLTP promoter activity relies primarily on the putative cis-elements in the functional region.