Phospholipid Transfer Proteins and their Regulatory Role in Lipid Metabolism and Potential Biological Functions

The phospholipid transfer protein (PLTP) is a lipid transfer glycoprotein that binds to and transfers a number of amphipathic compounds. In previous studies, the focus of the scientific community was on the specific role of PLTP in high-density lipoprotein (HDL) metabolism. Both PLTP and related cholesteryl ester transfer protein (CETP) are secreted proteins, and adipose tissue is an important contributor to the systemic pools of these two proteins. PLTP activity and its mRNA can be regulated by several factors. A diet rich in high-fat cholesterol results in a substantial increase in PLTP activity and in its mRNA levels. After a lipopolysaccharide injection, plasma PLTP activity is significantly reduced, and this is associated with a similar reduction in PLTP mRNA levels in the liver and adipose tissues. PLTP expression and activity can also be affect by glucose and insulin. This review article examines recent advances in the understanding of its potential biological roles.