Albers J J, Wolfbauer G, Cheung M C, Day J R, Ching A F, Lok S, Tu A Y
Department of Medicine, Northwest Lipid Research Laboratories, University of Washington, Seattle 98103, USA.
Biochim Biophys Acta. 1995 Aug 24;1258(1):27-34. doi: 10.1016/0005-2760(95)00091-p.
The molecular cloning of mouse plasma phospholipid transfer protein (PLTP) and the eukaryotic cell expression of complementary DNA for mouse and human PLTP are described. Mouse PLTP was found to share 83% amino acid sequence identity with human PLTP. PLTP was produced in baby hamster kidney cells. Conditioned medium from BHK cells expressing PLTP possessed both phospholipid transfer activity and high density lipoprotein (HDL) conversion activity. PLTP mRNA was detected in all 16 human tissues examined by Northern blot analysis with ovary, thymus, and placenta having the highest levels. PLTP mRNA was also examined in eight mouse tissues with the highest PLTP mRNA levels found in the lung, brain, and heart. The effect of purified human plasma-derived PLTP and human recombinant PLTP (rPLTP) on the two human plasma HDL subspecies Lp(A-I) and Lp(A-I/A-II) was evaluated. Plasma PLTP or rPLTP converted the two distinct size subspecies of Lp(A-I) into a larger species, an intermediate species, and a smaller species. Lp(A-I/A-II) particles containing multiple size subspecies were significantly altered by incubation with either plasma or rPLTP with the largest but less prominent subspecies becoming the predominant one, and the smallest subspecies increasing in concentration. Thus, PLTP promoted the conversion of both Lp(A-I) and Lp(A-I/A-II) to populations of larger and smaller particles. Also, both human PLTP and mouse rPLTP were able to convert human or mouse HDL into larger and smaller particles. These observations suggest that PLTP may play a key role in extracellular phospholipid transport and modulation of HDL particles.
本文描述了小鼠血浆磷脂转运蛋白（PLTP）的分子克隆以及小鼠和人PLTP互补DNA的真核细胞表达。发现小鼠PLTP与人PLTP的氨基酸序列一致性为83%。PLTP在幼仓鼠肾细胞中产生。表达PLTP的BHK细胞的条件培养基具有磷脂转运活性和高密度脂蛋白（HDL）转化活性。通过Northern印迹分析在所有检测的16种人体组织中均检测到PLTP mRNA，其中卵巢、胸腺和胎盘的水平最高。还在8种小鼠组织中检测了PLTP mRNA，在肺、脑和心脏中发现PLTP mRNA水平最高。评估了纯化的人血浆来源的PLTP和人重组PLTP（rPLTP）对两种人血浆HDL亚类Lp（A-I）和Lp（A-I/A-II）的影响。血浆PLTP或rPLTP将Lp（A-I）的两种不同大小亚类转化为一种较大的亚类、一种中间亚类和一种较小的亚类。含有多种大小亚类的Lp（A-I/A-II）颗粒在与血浆或rPLTP孵育后发生了显著改变，最大但不太明显的亚类成为主要亚类，最小亚类的浓度增加。因此，PLTP促进了Lp（A-I）和Lp（A-I/A-II）向更大和更小颗粒群体的转化。此外，人PLTP和小鼠rPLTP都能够将人或小鼠HDL转化为更大和更小的颗粒。这些观察结果表明，PLTP可能在细胞外磷脂转运和HDL颗粒调节中起关键作用。
