Jänis Minna T, Metso Jari, Lankinen Hilkka, Strandin Tomas, Olkkonen Vesa M, Rye Kerry-Anne, Jauhiainen Matti, Ehnholm Christian
Department of Molecular Medicine, National Public Health Institute, Biomedicum, P.O. Box 104, FIN-00251 Helsinki, Finland.
Biochem Biophys Res Commun. 2005 May 27;331(1):333-40. doi: 10.1016/j.bbrc.2005.03.164.
Phospholipid transfer protein (PLTP) exists in a high-activity (HA-PLTP) and a low-activity form (LA-PLTP) in the circulation. LA-PLTP is associated with apoA-I while the HA-PLTP complex is enriched with apoE. To study the interaction of PLTP with apolipoproteins, we carried out surface plasmon resonance analyses. These demonstrated a concentration-dependent binding of recombinant human PLTP, which represents an active PLTP form, and LA-PLTP to apoE, apoA-I, and apoA-IV within a nanomolar K(D) range. To study whether LA-PLTP can be transformed into an active form, we incubated it in the presence of proteoliposomes containing apoE, apoA-I or apoA-IV. The apoE proteoliposomes induced a concentration-dependent activation of LA-PLTP. ApoA-IV proteoliposomes also activated LA-PLTP in a concentration-dependent manner, whereas apoA-I proteoliposomes had no such effect. These observations suggest that PLTP is capable of interacting with apoE, apoA-I, and apoA-IV, and that these interactions regulate PLTP-activity levels in plasma.
磷脂转运蛋白（PLTP）在循环系统中以高活性形式（HA-PLTP）和低活性形式（LA-PLTP）存在。LA-PLTP与载脂蛋白A-I相关，而HA-PLTP复合物富含载脂蛋白E。为了研究PLTP与载脂蛋白的相互作用，我们进行了表面等离子体共振分析。结果表明，重组人PLTP（代表活性PLTP形式）和LA-PLTP在纳摩尔解离常数（K(D)）范围内与载脂蛋白E、载脂蛋白A-I和载脂蛋白A-IV呈浓度依赖性结合。为了研究LA-PLTP是否可以转化为活性形式，我们将其在含有载脂蛋白E、载脂蛋白A-I或载脂蛋白A-IV的蛋白脂质体存在下进行孵育。载脂蛋白E蛋白脂质体诱导LA-PLTP呈浓度依赖性激活。载脂蛋白A-IV蛋白脂质体也以浓度依赖性方式激活LA-PLTP，而载脂蛋白A-I蛋白脂质体则没有这种作用。这些观察结果表明，PLTP能够与载脂蛋白E、载脂蛋白A-I和载脂蛋白A-IV相互作用，并且这些相互作用调节血浆中PLTP的活性水平。
