Byrnes, JR, Wilson, C, Boutelle, AM et al. (4 more authors) (2016) The interaction between fibrinogen and zymogen FXIII-A₂B₂ is mediated by fibrinogen residues γ390-396 and the FXIII-B subunits. Blood, 128 (15). pp. 1969-1978. ISSN 0006-4971
Abstract
Coagulation transglutaminase factor XIII (FXIII) exists in circulation as heterotetrameric proenzyme FXIII-A2B2. Effectively all FXIII-A2B2 circulates bound to fibrinogen, and excess FXIII-B2 circulates in plasma. The motifs that mediate interaction of FXIII-A2B2 with fibrinogen have been elusive. We recently detected reduced binding of FXIII-A2B2 to murine fibrinogen that has γ-chain residues 390-396 mutated to alanines (Fibγ390-396A). Here, we evaluated binding features using human components, including recombinant fibrinogen variants, FXIII-A2B2, and isolated FXIII-A2 and -B2 homodimers. FXIII-A2B2 coprecipitated with wild-type (γA/γA), alternatively-spliced (γ′/γ′), and αC-truncated (Aα251) fibrinogens, whereas coprecipitation with human Fibγ390-396A was reduced by 75% (P < .0001). Surface plasmon resonance showed γA/γA, γ′/γ′, and Aα251 fibrinogens bound FXIII-A2B2 with high affinity (nanomolar); however, Fibγ390-396A did not bind FXIII-A2B2. These data indicate fibrinogen residues γ390-396 comprise the major binding motif for FXIII-A2B2. Compared with γA/γA clots, FXIII-A2B2 activation peptide release was 2.7-fold slower in Fibγ390-396A clots (P < .02). Conversely, activation of recombinant FXIII-A2 (lacking FXIII-B2) was similar in γA/γA and Fibγ390-396A clots, suggesting fibrinogen residues γ390-396 accelerate FXIII-A2B2 activation in a FXIII-B2–dependent mechanism. Recombinant FXIII-B2 bound γA/γA, γ′/γ′, and Aα251 with similar affinities as FXIII-A2B2, but did not bind or coprecipitate with Fibγ390-396A. FXIII-B2 also coprecipitated with fibrinogen from FXIII-A–deficient mouse and human plasmas. Collectively, these data indicate that FXIII-A2B2 binds fibrinogen residues γ390-396 via the B subunits, and that excess plasma FXIII-B2 is not free, but rather circulates bound to fibrinogen. These findings provide insight into assembly of the fibrinogen/FXIII-A2B2 complex in both physiologic and therapeutic situations.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 by The American Society of Hematology. This is an author produced version of a paper published in Blood. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Medicine (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 13 Nov 2018 13:26 |
Last Modified: | 17 Jan 2020 02:59 |
Status: | Published |
Publisher: | American Society of Hematology |
Identification Number: | 10.1182/blood-2016-04-712323 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:138515 |