Ogura M, Ito T, Maruyama I, Takamatsu J, Yamamoto S, Ogawa K, Nagura H, Saito H
First Dept. of Internal Medicine, Nagoya University School of Medicine, Japan.
Thromb Haemost. 1990 Oct 22;64(2):297-301.
The localization and biosynthesis of functional thrombomodulin (TM) on the cell surfaces of human platelets, megakaryocytes and a human megakaryoblastic cell line (MEG-01) were investigated. TM was demonstrated on the cell surfaces and in cytoplasms of human platelets, megakaryocytes and MEG-01 by an indirect immunofluorescent technique using monospecific rabbit anti-human TM serum. Immunoelectronmicroscopic analysis revealed that TM was localized in plasma membranes of MEG-01 cells as well as human megakaryocytes. 125I-monoclonal antithrombomodulin IgG binding assay showed that one MEG-01 cell possessed approximately 78,000 TM molecules on its cell surface. Thrombin-dependent protein C activating-cofactor activity was demonstrated on MEG-01 cells. Northern hybridization technique using cDNA probe of TM revealed that poly(A)(+)-RNA from MEG-01 cells showed a single band of 3.8 kb similar to that from human endothelial cells. These data suggest that human megakaryocytes synthesize functional TM, and thereby platelets possess TM on their surfaces. TM on platelets may participate in the activation of protein C at the site of a hemostatic plug.
对人血小板、巨核细胞及人巨核母细胞系（MEG - 01）细胞表面功能性血栓调节蛋白（TM）的定位及生物合成进行了研究。通过使用单特异性兔抗人TM血清的间接免疫荧光技术，在人血小板、巨核细胞及MEG - 01的细胞表面和细胞质中证实了TM的存在。免疫电子显微镜分析显示，TM定位于MEG - 01细胞以及人巨核细胞的质膜中。125I - 单克隆抗血栓调节蛋白IgG结合试验表明，一个MEG - 01细胞在其细胞表面约有78,000个TM分子。在MEG - 01细胞上证实了凝血酶依赖性蛋白C激活辅因子活性。使用TM的cDNA探针的Northern杂交技术显示，来自MEG - 01细胞的聚腺苷酸（+）-RNA显示出一条3.8 kb的单带，与人内皮细胞的相似。这些数据表明，人巨核细胞合成功能性TM，因此血小板在其表面具有TM。血小板上的TM可能在止血栓部位参与蛋白C的激活。
