Novel expression and localization of active thrombomodulin on the surface of mouse brain astrocytes.
Thrombin's potent effects on astrocytes are mediated by a specific receptor and inhibited by a serpin, protease nexin I (PNI). Thrombomodulin (TM), a membrane protein that forms complexes with thrombin, changing its enzymatic specificity, has not been studied in astrocytes. In primary astrocyte cultures, using Western blotting and immunocytochemistry, we found a 70 kDa TM band and TM localized to the surface with an anti-mouse TM monoclonal antibody. By reverse transcriptase coupled with polymerase chain reaction (RT-PCR), we found the correct sequence for mouse TM mRNA in astrocytes. Finally, we documented calcium-dependent activation of protein C by a thrombin:TM complex with thrombin added to the astrocytes. These results indicate the presence of functionally active TM at the astrocyte surface and add support to a role for thrombin signaling in the nervous system.
Pindon
A
A
I.N.S.E.R.M. Unité 153, Paris, France.
Hantai
D
D
Jandrot-Perrus
M
M
Festoff
B W
BW
D000818:Animals; D001253:Astrocytes / Q000737:chemistry*; D015153:Blotting, Western; D001921:Brain / Q000166:cytology; D001923:Brain Chemistry; D002462:Cell Membrane / Q000737:chemistry; D002478:Cells, Cultured; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D051379:Mice; D016133:Polymerase Chain Reaction; D012194:RNA-Directed DNA Polymerase; D051381:Rats; D018180:Thrombomodulin / Q000032:analysis* / Q000235:genetics
D018180:Thrombomodulin; D012194:RNA-Directed DNA Polymerase