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Schreuder M, Poenou G, Strijbis VJF, Cheung KL, Reitsma PH, Bos MHA. Evolutionary Adaptations in Pseudonaja Textilis Venom Factor X Induce Zymogen Activity and Resistance to the Intrinsic Tenase Complex. Thromb Haemost 2020; 120:1512-1523. [PMID: 32820486 DOI: 10.1055/s-0040-1715441] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The venom of the Australian snake Pseudonaja textilis comprises powerful prothrombin activators consisting of factor X (v-ptFX)- and factor V-like proteins. While all vertebrate liver-expressed factor X (FX) homologs, including that of P. textilis, comprise an activation peptide of approximately 45 to 65 residues, the activation peptide of v-ptFX is significantly shortened to 27 residues. In this study, we demonstrate that exchanging the human FX activation peptide for the snake venom ortholog impedes proteolytic cleavage by the intrinsic factor VIIIa-factor IXa tenase complex. Furthermore, our findings indicate that the human FX activation peptide comprises an essential binding site for the intrinsic tenase complex. Conversely, incorporation of FX into the extrinsic tissue factor-factor VIIa tenase complex is completely dependent on exosite-mediated interactions. Remarkably, the shortened activation peptide allows for factor V-dependent prothrombin conversion while in the zymogen state. This indicates that the active site of FX molecules comprising the v-ptFX activation peptide partially matures upon assembly into a premature prothrombinase complex. Taken together, the shortened activation peptide is one of the remarkable characteristics of v-ptFX that has been modified from its original form, thereby transforming FX into a powerful procoagulant protein. Moreover, these results shed new light on the structural requirements for serine protease activation and indicate that catalytic activity can be obtained without formation of the characteristic Ile16-Asp194 salt bridge via modification of the activation peptide.
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Affiliation(s)
- Mark Schreuder
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Geraldine Poenou
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands.,AP-HP, Hôpital Louis Mourier, Colombes, France
| | - Viola J F Strijbis
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Ka Lei Cheung
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Pieter H Reitsma
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
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Nagaya S, Akiyama M, Murakami M, Sekiya A, Asakura H, Morishita E. Congenital coagulation factor X deficiency: Genetic analysis of five patients and functional characterization of mutant factor X proteins. Haemophilia 2018; 24:774-785. [DOI: 10.1111/hae.13606] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/27/2018] [Accepted: 07/30/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Satomi Nagaya
- Asanogawa General Hospital; Kanazawa Ishikawa Japan
- Department of Clinical Laboratory Science; Kanazawa University Graduate School of Medical Science; Kanazawa Ishikawa Japan
| | - Masashi Akiyama
- Department of Molecular Pathogenesis; National Cerebral and Cardiovascular Center Research Institute; Osaka Japan
| | - Morika Murakami
- Department of Clinical Laboratory Science; Kanazawa University Graduate School of Medical Science; Kanazawa Ishikawa Japan
| | - Akiko Sekiya
- Department of Clinical Laboratory Science; Kanazawa University Graduate School of Medical Science; Kanazawa Ishikawa Japan
| | - Hidesaku Asakura
- Department of Hematology; Kanazawa University Hospital; Kanazawa Ishikawa Japan
| | - Eriko Morishita
- Department of Clinical Laboratory Science; Kanazawa University Graduate School of Medical Science; Kanazawa Ishikawa Japan
- Department of Hematology; Kanazawa University Hospital; Kanazawa Ishikawa Japan
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Baroni M, Pavani G, Pinotti M, Branchini A, Bernardi F, Camire RM. Asymmetric processing of mutant factor X Arg386Cys reveals differences between intrinsic and extrinsic pathway activation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1351-6. [PMID: 26012870 DOI: 10.1016/j.bbapap.2015.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/30/2015] [Accepted: 05/18/2015] [Indexed: 01/30/2023]
Abstract
Alterations in coagulation factor X (FX) activation, mediated by the extrinsic VIIa/tissue factor (FVIIa/TF) or the intrinsic factor IXa/factor VIIIa (FIXa/FVIIIa) complexes, can result in hemorrhagic/prothrombotic tendencies. However, the molecular determinants involved in substrate recognition by these enzymes are poorly defined. Here, we investigated the role of arginine 386 (chymotrypsin numbering c202), a surface-exposed residue on the FX catalytic domain. The naturally occurring FX386Cys mutant and FX386Ala variant were characterized. Despite the unpaired cysteine, recombinant (r)FX386Cys was efficiently secreted (88.6±21.3% of rFXwt) and possessed normal clearance in mice. rFX386Cys was also normally activated by FVIIa/TF and displayed intact amidolytic activity. In contrast, rFX386Cys activation by the FIXa/FVIIIa complex was 4.5-fold reduced, which was driven by a decrease in the kcat (1.6∗10(-4) s(-1) vs 5.8∗10(-4) s(-1), rFXwt). The virtually unaltered Km (70.6 nM vs 55.6nM, rFXwt) suggested no major alterations in the FX substrate exosite. Functional assays in plasma supplemented with rFX386Cys indicated a remarkable reduction in the thrombin generation rate and thus in coagulation efficiency. Consistently, the rFX386Ala variant displayed similar biochemical features suggesting that global changes at position 386 impact the intrinsic pathway activation. These data indicate that the FXArg386 is involved in FIXa/FVIIIa-mediated FX activation and help in elucidating the bleeding tendency associated with the FX386Cys in a rare FX deficiency case. Taking advantage of the unpaired cysteine, the rFX386Cys mutant may be efficiently targeted by thiol-specific ligands and represent a valuable tool to study FX structure-function relationships both in vitro and in vivo.
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Affiliation(s)
- M Baroni
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy.
| | - G Pavani
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy; The Children's Hospital of Philadelphia, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; The Center for Cell and Molecular Therapeutics, and Division of Hematology, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Pediatrics, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - M Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy
| | - A Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy
| | - F Bernardi
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy
| | - R M Camire
- The Children's Hospital of Philadelphia, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; The Center for Cell and Molecular Therapeutics, and Division of Hematology, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Pediatrics, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
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Abstract
BACKGROUND Many genome-wide association studies focus on associating single loci with target phenotypes. However, in the setting of rare variation, accumulating sufficient samples to assess these associations can be difficult. Moreover, multiple variations in a gene or a set of genes within a pathway may all contribute to the phenotype, suggesting that the aggregation of variations found over the gene or pathway may be useful for improving the power to detect associations. RESULTS Here, we present a method for aggregating single nucleotide polymorphisms (SNPs) along biologically relevant pathways in order to seek genetic associations with phenotypes. Our method uses all available genetic variants and does not remove those in linkage disequilibrium (LD). Instead, it uses a novel SNP weighting scheme to down-weight the contributions of correlated SNPs. We apply our method to three cohorts of patients taking warfarin: two European descent cohorts and an African American cohort. Although the clinical covariates and key pharmacogenetic loci for warfarin have been characterized, our association metric identifies a significant association with mutations distributed throughout the pathway of warfarin metabolism. We improve dose prediction after using all known clinical covariates and pharmacogenetic variants in VKORC1 and CYP2C9. In particular, we find that at least 1% of the missing heritability in warfarin dose may be due to the aggregated effects of variations in the warfarin metabolic pathway, even though the SNPs do not individually show a significant association. CONCLUSIONS Our method allows researchers to study aggregative SNP effects in an unbiased manner by not preselecting SNPs. It retains all the available information by accounting for LD-structure through weighting, which eliminates the need for LD pruning.
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