Phospholipid transfer proteins from lung, properties and possible physiological functions.

Phospholipid transfer proteins have been found in lung just as they have in tissues throughout the body. There is speculation that the proteins are involved in membrane biogenesis and in determining the phospholipid composition of membranes. For this reason the lung, which contains subcellular organelles of distinct phospholipid composition, is of interest in terms of its complement of phospholipid transfer proteins. The lamellar bodies of pulmonary type II alveolar cells have a phospholipid composition unique in terms of the proportions of dipalmitoyl phosphatidylcholine and phosphatidylglycerol. Studies of the phospholipid transfer proteins in lung have demonstrated two molecular species of the transfer proteins that differ significantly from those found in liver and other tissues. These proteins show specificity for the transfer of dipalmitoyl phosphatidylcholine and phosphatidylglycerol.