title: Cross-linking of plasminogen activator inhibitor 2 and alpha 2-antiplasmin to fibrin(ogen).
abstract: In this study, we identified lysine residues in the fibrinogen Aalpha chain that serve as substrates during transglutaminase (TG)-mediated cross-linking of plasminogen activator inhibitor 2 (PAI-2). Comparisons were made with alpha(2)-antiplasmin (alpha(2)-AP), which is known to cross-link to lysine 303 of the Aalpha chain. A 30-residue peptide containing Lys-303 specifically competed with fibrinogen for cross-linking to alpha(2)-AP but not for cross-linking to PAI-2. Further evidence that PAI-2 did not cross-link via Lys-303 was the cross-linking of PAI-2 to I-9 and des-alphaC fibrinogens, which lack 100 and 390 amino acids from the C terminus of the Aalpha chain, respectively. PAI-2 or alpha(2)-AP was cross-linked to fibrinogen and digested with trypsin or endopeptidase Glu-C, and the resulting peptides analyzed by mass spectrometry. Peptides detected were consistent with tissue TG (tTG)-mediated cross-linking of PAI-2 to lysines 148, 176, 183, 457 and factor XIIIa-mediated cross-linking of PAI-2 to lysines 148, 230, and 413 in the Aalpha chain. alpha(2)-AP was cross-linked only to lysine 303. Cross-linking of PAI-2 to fibrinogen did not compete with alpha(2)-AP, and the two proteins utilized different lysines in the Aalpha chain. Therefore, PAI-2 and alpha(2)-AP can cross-link simultaneously to the alpha polymers of a fibrin clot and promote resistance to lysis.
authors.affiliation: Department of Molecular and Cell Biology, University of Aberdeen, Institute of Medical Sciences, Aberdeen, United Kingdom AB25 2ZD.
authors.forename: H
authors.initials: H
authors.lastname: Ritchie
authors.forename: L C
authors.initials: LC
authors.lastname: Lawrie
authors.forename: P W
authors.initials: PW
authors.lastname: Crombie
authors.forename: M W
authors.initials: MW
authors.lastname: Mosesson
authors.forename: N A
authors.initials: NA
authors.lastname: Booth
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003432:Cross-Linking Reagents; D005337:Fibrin / Q000737:chemistry / Q000378:metabolism*; D005340:Fibrinogen / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008239:Lysine; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D017396:Plasminogen Activator Inhibitor 2 / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D011503:Transglutaminases / Q000378:metabolism; D014357:Trypsin; D000979:alpha-2-Antiplasmin / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D010446:Peptide Fragments; D017396:Plasminogen Activator Inhibitor 2; D011994:Recombinant Proteins; D000979:alpha-2-Antiplasmin; D005337:Fibrin; D005340:Fibrinogen; D011503:Transglutaminases; D014357:Trypsin; D008239:Lysine