Thromb Haemost 1990; 64(02): 297-301
DOI: 10.1055/s-0038-1647305
Original Article
Schattauer GmbH Stuttgart

Localization and Biosynthesis of Functional Thrombomodulin in Human Megakaryocytes and a Human Megakaryoblastic Cell Line (MEG-01)

Michinori Ogura
1   The First Dept. of Internal Medicine, Nagoya University School of Medicine, Japan
*   The Present address: the Department of Hematology and Cancer Chemotherapeutics, Aichi Cancer Center Hospital, Nagoya, Japan
,
Takahiko Ito
1   The First Dept. of Internal Medicine, Nagoya University School of Medicine, Japan
,
Ikuro Maruyama
2   The Third Dept. of Internal Medicine, Kogoshima University School of Medicine, Japan
,
Junki Takamatsu
1   The First Dept. of Internal Medicine, Nagoya University School of Medicine, Japan
,
Shuji Yamamoto
3   The Bio-Science Laboratory, Life Science Research Laboratories, Asahi Chemical Industry, Japan
,
Kohei Ogawa
3   The Bio-Science Laboratory, Life Science Research Laboratories, Asahi Chemical Industry, Japan
,
Hiroshi Nagura
4   The Second Dept. of Pathology, Tohoku University School of Medicine, Japan
,
Hidehiko Saito
1   The First Dept. of Internal Medicine, Nagoya University School of Medicine, Japan
› Author Affiliations
Further Information

Publication History

Received 27 February 1990

Accepted after revision28 May 1990

Publication Date:
25 July 2018 (online)

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Summary

The localization and biosynthesis of functiosnal 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.