Signal Transduction Mechanisms Mediating Surfactant Phospholipid Secretion in Isolated Type II Cell.

Park, Sung Soo

doi:1996.43.2.123

Tuberc Respir Dis > Volume 43(2); 1996 > Article

Review Article

Tuberculosis and Respiratory Diseases 1996;43(2):123-127.
DOI: https://doi.org/10.4046/trd.1996.43.2.123 Published online April 1, 1996.

Signal Transduction Mechanisms Mediating Surfactant Phospholipid Secretion in Isolated Type II Cell.

Sung Soo Park

Department of Pulmonary Medicine, College of Medicine, Hanyang University, Seoul, Korea.

Abstract

Secretion of surfactant phospholipid can be stimulated by a variety of agonists acting via at least three different signal transduction mechanisms. These include the adenylate cyclase system with activation of cAMP-dependent protein kinase; activation of protein kinase C either directly or subsequent to activation of phosphoinositide-specific phospholipase C and generation of diacylglycerols and inositol trisphosphate; and a third mechanism that involves incresed Ca2+ levels and a calmodulin-dependent step. ATP stimulates secretion via all three mechanisms. The protein kinase C pathway is also coupled to phopholipase D which, acting on relatively abundant cellular phospholipids, generates diacylglycerols that further activate protein kinase C. Sustained protein kinase C activation can maintain phosphatidylcholine secretion for a prolonged period of time. It is likely that interactions between the different signaling pathways have an important role in the overall physiological regulation of surfactant secretion.

Key Words: Signal transduction mechanisms, Surfactant phospholipid secretion, Isolated type II cell