Study on the mechanism of the annexin II-mediated Co-assembly of t-PA and plasminogen

Abstract

In order to further investigate the effect of annexin II (Ann-II) on tissue plasminogen activator (t-PA)-dependent plasminogen (PLG) activation and its interactive mechanism, recombinant native Ann-II bound t-PA, PLG and plasmin with high affinity was examined. The flow cytometric assay showed that the ann-II expression rate was higher in the human umbilical vein endothelial cell (HUVEC) (87.65%) than in the HL-60 cells as controls (35.79%). Two irrelevant proteins, bovine serum albumin (BSA) and equine IgG (EIG) had no effect on the production of plasmin. Ann-II-mediated enhancement of t-PA-dependent PLG activation was inhibited by ε-aminocaproic acid or by pretreatment of Ann-II with carboxypeptidase B with the inhibitive rate being 77.8% and 77.0%, respectively. It was revealed that the effect of Ann-II on PLG activation was specific for t-PA. Urokinase didn't bind to Ann-II, demonstrating the role of receptor-related lysine residues on activation of PLG, showing that the Ann-II-PLG interaction was dependent upon carboxyl-terminal lysine residues. These findings suggest that annexin II-mediated co-assembly of t-PA and PLG may promote plasmin generation and play a key role in modulating fibrinolysis on the endothelial surface.

Keywords

annexin II / plasminogen / tissue plasminogen activator / co-receptor / activation

References

[1] JostM, WeberK, GerkeV. Annexin II contains two types of Ca(2+)-binding sites. Biochem J, 1994, 298(3): 553-553

[2] HajjarK A, MenellJ S. Annexin II: a novel mediator of cell surface plasmin generation. Ann N Y Acad Sci, 1997, 811: 337-337

[3] HajjarK A, MauriL, JacovinaA T, et al. . Tissue plasminogen activator binding to the annexin II tail domain. J Biol Chem, 1998, 273(16): 9987-9987

[4] RedlitzA, PlowE F. Receptors for plasminogen and t-PA: an update. Baillieres Clin Haematol, 1995, 8(2): 313-313

[5] HajjarK A, KrishnanS. Annexin II: a mediator of the plasmin/plasminogen activator system. Trends Cardiovasc Med, 1999, 9(5): 128-128

[6] RandJ H. The annexinopathies: a new category of diseases. Biochim Biophys Acta, 2000, 1498(2–3): 169-169

[7] HajjarK A, GuevaraC A, LevE, et al. . Interaction of the fibrinolytic receptor, annexin II, with the endothelial cell surface. Essential role of endonexin repeat. J Biol Chem, 1996, 271: 21652-21652

[8] MenellJ S, CesarmanG M, JacovinaA T, et al. . Annexin II and bleeding in acute promyelocytic leukemia. N Engl J Med, 1999, 340(13): 994-994

[9] ChoiK S, FitzpatrickS L, FilipenkoN R, et al. . Regulation of plasmin-dependent fibrin clot lysis by annexin II heterotetramer. J Biol Chem, 2001, 276(27): 25212-25212

[10] CesarmanG M, GuevaraC A, HajjarK A. An endothelial cell receptor for plasminogen/tissue plasminogen activator (t-PA). II. Annexin II-mediated enhancement of t-PA-dependent plasminogen activation. J Biol Chem, 1994, 269(33): 21198-21198