Apolipoprotein F (Apo F (or LTIP))

Apolipoprotein F (Lipid transfer inhibitor protein, LTIP) is a plasma protein that modulates the function of cholesteryl ester transfer protein (CETP) by preferentially blocking its activity on low-density lipoproteins (LDL)[3]. LTIP exists in both active (LDL-associated) and inactive (470 kDa complex) forms, the activity of which can be regulated by plasma lipid composition and enzymatic activity, notably by CETP and lecithin-cholesterol acyltransferase (LCAT)[3][1]. By selectively inhibiting lipid transfer to or from LDL, LTIP influences the net movement of cholesterol esters, facilitating reverse cholesterol transport, which is critical for cholesterol homeostasis and cardiovascular risk[3][1]. LTIP does not directly bind CETP, but rather prevents CETP binding to LDL surfaces[3]. It is distinct from plant lipid transfer proteins, which have unrelated structure and function[5]. Key scientific distinction: "Lipid transfer inhibitor protein" strictly refers to the apolipoprotein F in mammals/humans, not to plant lipid transfer proteins. Its main molecular function is as a modulator of plasma cholesterol and triglyceride exchange, and it is a candidate therapeutic target in cardiovascular and metabolic diseases[3][1].

Other names

Lipid transfer inhibitor proteinLTIPApo F

Drugs would likely act by modulation (inhibition or enhancement) of LTIP function to alter cholesterol and triglyceride transport Modifies CETP-mediated lipid exchange by blocking CETP binding to LDL; thus, regulating cholesterol efflux