A Bipartite Autoinhibitory Region within the B-domain Suppresses Function in Factor V

Bos, Mettine H.A.; Camire, Rodney M.

doi:10.1074/jbc.m112.377168

Cited by 56 publications

(107 citation statements)

References 65 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…The basic region is tightly bound to an acidic region in the B domain, which is an interaction important to maintain FV in an inactive state. 3,4 TFPI has a similar basic region in its C terminus that can tightly interact with the acidic region in the B domain of FV. The increased levels of TFPI in individuals with factor V Amsterdam could produce an anticoagulant effect by increasing factor Xa inhibition (with protein S), increasing factor VIIa/tissue factor inhibition, and inhibiting prothrombinase.…”

Section: Resultsmentioning

confidence: 99%

A novel mutation in the F5 gene (factor V Amsterdam) associated with bleeding independent of factor V procoagulant function

Cunha

Bakhtiari²,

Peter³

et al. 2015

Blood

View full text Add to dashboard Cite

Key Points• A novel gain-of-function mutation in factor V leading to increased levels of TFPI and bleeding was identified by whole exome sequencing.• Factor V Amsterdam (F5 C2588G) resembles the mutation (F5 A2350G) leading to East Texas bleeding disorder.We investigated a small Dutch family with a bleeding diathesis, prolonged prothrombin, and activated partial thromboplastin times, in whom no classifying diagnosis was made. The 2 affected relatives had severely decreased in vitro thrombin generation, and levels of tissue factor pathway inhibitor (TFPI) were strongly increased. To identify the genetic cause of the bleeding diathesis, we performed whole exome sequencing analysis of all living relatives. We found a novel gain-of-function mutation in the F5 gene (c.C2588G), which leads to an aberrant splicing of F5 and ultimately to a short factor V protein (missing 623 amino acids from the B domain), which we called factor V Amsterdam. Factor V Amsterdam binds to TFPI, prolonging its half-life and concentration. This is the second report of an association between a shorter form of factor V and increased TFPI levels, resulting in severely reduced thrombin generation and a bleeding tendency. (Blood. 2015; 125(11):1822-1825 IntroductionIn clinical practice, we occasionally encounter patients with a bleeding tendency and prolonged coagulation screening tests, in whom a classifying diagnosis cannot be made. Here, we describe our search toward elucidating the etiology of a bleeding tendency in a mother and her son. Study design Subjects and samplesThe pedigree of the family is depicted in Figure 1A. Detailed clinical features of the family are provided in supplemental Table 1, available on the Blood Web site. We collected blood from the mother (II:2) and son (III:1) with clinical manifestations of bleeding and 4 unaffected relatives. All participants provided written informed consent. Coagulation testing and exome sequencingCoagulation parameters were determined by standard methods. Thrombin generation was performed with calibrated automated thrombography. Genomic DNA was isolated from peripheral blood mononuclear cells. Direct exome sequencing of the TFPI and PROS1 genes was performed in the 2 patients and 1 unaffected relative. Whole exome sequencing data were generated for all relatives, and candidate mutations were confirmed by Sanger sequencing. Details of methods are available in supplemental Materials. Results and discussionThrombin generation was measured in plasma from individuals II:1 (unaffected husband), II:2 (proband), and III:1 (affected son). Thrombin generation initiated with 1 pM tissue factor was severely affected in the proband and son ( Figure 1B); this also occurred at higher concentrations of tissue factor (5 pM, Figure 1C; 20 pM, data not shown). Mixing patient plasma with normal plasma did not normalize thrombin generation, suggesting the presence of a circulating inhibitor (data not shown). Because lupus anticoagulant and deficiencies of antithrombin and protein C had been excluded in both pat...

show abstract

Section: Resultsmentioning

confidence: 99%

A novel mutation in the F5 gene (factor V Amsterdam) associated with bleeding independent of factor V procoagulant function

Cunha

Bakhtiari²,

Peter³

et al. 2015

Blood

View full text Add to dashboard Cite

show abstract

“…Further studies will determine the details of the TFPIα binding to normal FV/FVa and to FV-short and address the question as to why TFPIα preferentially binds the FV-short isoform rather than the FV-FL. A recent paper by Bos and Camire (32) reported that 2 regions in the B domain are important to keep FV in a procofactor state -one being positively charged (963-1008) and the other, close to the 1545 thrombin-cleavage site (1493-1537), being negatively charged. Deletions in recombinant FV of either the basic or the acidic cluster yielded FV in an active state.…”

Section: Figurementioning

confidence: 99%

Coagulation factor VA2440G causes east Texas bleeding disorder via TFPIα

et al. 2013

View full text Add to dashboard Cite

The autosomal dominantly inherited east Texas bleeding disorder is linked to an A2440G variant in exon 13 of the F5 gene. Affected individuals have normal levels of coagulation factor V (FV) activity, but demonstrate inhibition of global coagulation tests. We demonstrated that the A2440G mutation causes upregulation of an alternatively spliced F5 transcript that results in an in-frame deletion of 702 amino acids of the large activation fragment, the B domain. The approximately 250-kDa FV isoform (FV-short), which can be fully activated by thrombin, is present in all A2440G carriers' plasma (n = 16). FV-short inhibits coagulation through an indirect mechanism by forming a complex with tissue factor pathway inhibitor-α (TFPIα), resulting in an approximately 10-fold increase in plasma TFPIα, suggesting that the TFPIα:FV-short complexes are retained in circulation. The TFPIα:FV-short complexes efficiently inhibit thrombin generation of both intrinsic and extrinsic coagulation pathways. These data demonstrate that the east Texas bleeding disorder-associated F5 A2440G leads to the formation of the TFPIα:FV-short complex, which inhibits activation and propagation of coagulation. IntroductionCoagulation factor V (FV) is a cofactor protein that can both promote and inhibit coagulation (1, 2). Located on 1q24-25, the F5 gene is composed of 25 exons that transcribe a 6.8-kb mRNA (3-7). The translated 330-kDa glycoprotein precursor contains 2,196 amino acids organized into the domain structure A1-A2-B-A3-C1-C2 and is highly homologous to factor VIII (FVIII), sharing 35%-40% identity in the A and C domains (4, 5, 8). Human FV is primarily produced by hepatocytes and circulates in plasma as an intact 330-kDa precursor at a concentration of about 20 nM (7 μg/ml) (9-12). Approximately 20% of the total human FV found in whole blood is stored in platelet α granules in a partially proteolyzed form in conjunction with the binding protein multimerin. This platelet FV derives from the plasma FV pool and is secreted upon platelet activation to create a high, localized concentration of the cofactor at sites of injury (12)(13)(14)(15).The procoagulant cofactor function of FV is primarily dictated by its interaction and cleavage by thrombin and active factor X (FXa). Its cleavage by thrombin is deemed the most biologically important early event in the blood clot formation process (16)(17)(18)(19). As an intact single-chain precursor, FV expresses less than 1% of its potential procoagulant cofactor activity (20). Upon sequential cleavage of Arg-709, Arg-1018, and Arg-1545 by thrombin, the large connecting B domain is removed from the intact FV molecule to produce the heavy chain (A1-A2) and the light chain (A3-C1-C2) that have M r s of 105,000 and 74,000, respectively. The heavy chain and the light chain noncovalently associate in the presence of calcium to produce an active procoagulant cofactor (FVa). FVa and FXa assemble on negatively charged phospholipid (PL) membranes to form the prothrombinase (PTase) complex. The presence of FVa in...

show abstract

“…The BR and the AR interact with each other and maintain FV in its inactive state (52,53). Removal of either the BR or the AR results in a constitutively active FVa molecule, and removal of both regions yields the fully active FVa molecule (52,53). Further, similar to the BR of FV, the C-terminal regions of TFPI-1 and TFPI-2 contain several Arg and Lys residues (1)(2)(3).…”

mentioning

confidence: 99%

“…The B-domain contains two highly conserved sequences, termed the basic region (BR, residues 963-1008) and the acidic region (AR, residues 1493-1537). The BR and the AR interact with each other and maintain FV in its inactive state (52,53). Removal of either the BR or the AR results in a constitutively active FVa molecule, and removal of both regions yields the fully active FVa molecule (52,53).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Platelets Contain Tissue Factor Pathway Inhibitor-2 Derived from Megakaryocytes and Inhibits Fibrinolysis

Vadivel

Ponnuraj

Kumar

et al. 2014

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Background: TFPI-2 inhibits plasma kallikrein, FXIa, and plasmin, but its concentration in normal plasma is insufficient to inhibit clotting or fibrinolysis. Results: Platelets contain TFPI-2 derived from megakaryocytes and binds to platelet FV/Va and circulating FV in late pregnancy when plasma TFPI-2 is ϳ7 nM. Conclusion: Platelet-derived TFPI-2 regulates intrinsic coagulation and tPA-induced fibrinolysis. Significance: Platelet-derived TFPI-2 promotes clot stabilization while attenuating intrinsic clotting.

show abstract

A Bipartite Autoinhibitory Region within the B-domain Suppresses Function in Factor V

Cited by 56 publications

References 65 publications

A novel mutation in the F5 gene (factor V Amsterdam) associated with bleeding independent of factor V procoagulant function

A novel mutation in the F5 gene (factor V Amsterdam) associated with bleeding independent of factor V procoagulant function

Coagulation factor VA2440G causes east Texas bleeding disorder via TFPIα

Platelets Contain Tissue Factor Pathway Inhibitor-2 Derived from Megakaryocytes and Inhibits Fibrinolysis

Contact Info

Product

Resources

About