Retention of thrombin inhibitory activity by recombinant serpins expressed as integral membrane proteins tethered to the surface of mammalian cells

BACKGROUND: Serpins form a widely distributed protein superfamily, but no integral membrane serpins have been described. OBJECTIVES: To anchor three serpins -α(1) -proteinase inhibitor (α(1) PI) (M358R), antithrombin (AT), and heparin cofactor II (HCII) - in the plasma membranes of transfected mammalian cells and assess their ability to inhibit thrombin.