Khubchandani K R, Snyder J M
Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
FASEB J. 2001 Jan;15(1):59-69. doi: 10.1096/fj.00-0318rev.
Surfactant protein A (SP-A) is the major protein component of pulmonary surfactant, a material secreted by the alveolar type II cell that reduces surface tension at the alveolar air-liquid interface. The function of SP-A in the alveolus is to facilitate the surface tension-lowering properties of surfactant phospholipids, regulate surfactant phospholipid synthesis, secretion, and recycling, and counteract the inhibitory effects of plasma proteins released during lung injury on surfactant function. It has also been shown that SP-A modulates host response to microbes and particulates at the level of the alveolus. More recently, several investigators have reported that pulmonary surfactant phospholipids and SP-A are present in nonalveolar pulmonary sites as well as in other organs of the body. We describe the structure and possible functions of alveolar SP-A as well as the sites of extra-alveolar SP-A expression and the possible functions of SP-A in these sites.
表面活性蛋白A（SP-A）是肺表面活性剂的主要蛋白质成分，肺表面活性剂是由II型肺泡细胞分泌的一种物质，可降低肺泡气液界面的表面张力。SP-A在肺泡中的功能是促进表面活性剂磷脂降低表面张力的特性，调节表面活性剂磷脂的合成、分泌和再循环，并抵消肺损伤期间释放的血浆蛋白对表面活性剂功能的抑制作用。研究还表明，SP-A在肺泡水平调节宿主对微生物和颗粒物的反应。最近，一些研究人员报告称，肺表面活性剂磷脂和SP-A不仅存在于非肺泡肺部位，也存在于身体的其他器官中。我们描述了肺泡SP-A的结构和可能的功能，以及肺泡外SP-A的表达部位和SP-A在这些部位可能的功能。
