The Interaction of Integrin αIIbβ3 with Fibrin Occurs through Multiple Binding Sites in the αIIb β-Propeller Domain

Podolnikova, Nataly P.; Yakovlev, Sergiy; Yakubenko, Valentin P.; Wang, Xu; Gorkun, Oleg V.; Ugarova, Tatiana P.

doi:10.1074/jbc.m113.518126

Cited by 49 publications

(46 citation statements)

References 57 publications

(78 reference statements)

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“…6,31 One explanation for the persistent fibrin(ogen) binding to platelets with apparently inactive integrins, is that the activated α IIb b 3 displays distinct binding sites for fibrinogen and fibrin, allowing interaction with fibrin, independently of the classical integrin activation domains. 32 However, in the present study, we observed that the high fibrin(ogen) binding of washed platelets was antagonized by combined inhibition of α IIb b 3 and transglutaminases. This suggests initial binding of fibrinogen to the activated integrin, followed by secondary binding of a growing fibrin fiber to platelet surface proteins via transglutaminase activity.…”

contrasting

confidence: 47%

Coated platelets function in platelet-dependent fibrin formation via integrin α _IIb β ₃ and transglutaminase factor XIII

et al. 2015

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C oated platelets, formed by collagen and thrombin activation, have been characterized in different ways: i) by the formation of a protein coat of α-granular proteins; ii) by exposure of procoagulant phosphatidylserine; or iii) by high fibrinogen binding. Yet, their functional role has remained unclear. Here we used a novel transglutaminase probe, Rhod-A14, to identify a subpopulation of platelets with a cross-linked protein coat, and compared this with other platelet subpopulations using a panel of functional assays. Platelet stimulation with convulxin/thrombin resulted in initial integrin α IIb b 3 activation, the appearance of a platelet population with high fibrinogen binding, (independently of active integrins, but dependent on the presence of thrombin) followed by phosphatidylserine exposure and binding of coagulation factors Va and Xa. A subpopulation of phosphatidylserine-exposing platelets bound Rhod-A14 both in suspension and in thrombi generated on a collagen surface. In suspension, high fibrinogen and Rhod-A14 binding were antagonized by combined inhibition of transglutaminase activity and integrin α IIb b 3 . Markedly, in thrombi from mice deficient in transglutaminase factor XIII, platelet-driven fibrin formation and Rhod-A14 binding were abolished by blockage of integrin α IIb b 3 . Vice versa, star-like fibrin formation from platelets of a patient with deficiency in α IIb b 3 (Glanzmann thrombasthenia) was abolished upon blockage of transglutaminase activity. We conclude that coated platelets, with initial α IIb b 3 activation and high fibrinogen binding, form a subpopulation of phosphatidylserine-exposing platelets, and function in platelet-dependent star-like fibrin fiber formation via transglutaminase factor XIII and integrin α IIb b 3 .

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contrasting

confidence: 47%

Coated platelets function in platelet-dependent fibrin formation via integrin α _IIb β ₃ and transglutaminase factor XIII

et al. 2015

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“…They also identified 8 separate negatively charged sites on the aIIb b-propeller as potential binding sites for the positively charged g-370-381 peptide. 38 Podolinikova et al also studied the impact of P3 on platelet adhesion to D98. 24 Using gel-filtered, calcein-labeled platelets in the presence of 1 mM MgCl 2 , 1 mM CaCl 2 , they found that adhesion of unactivated platelets to D98 was ;45% of the adhesion to fibrinogen fragment D100, which contains an intact g-12 peptide.…”

Section: Discussionmentioning

confidence: 99%

“…Heavy atoms of 4 residues on the aIIb helix, Leu151, Arg153, Ile154, and Asn158, are within 5Å from 10E5 in the 10E5-aIIbb3 headpiece crystal structure 2VDO (supplemental Figure 6), suggesting that our model is consistent with competitive binding between fibrinogen/'D98' and 10E5. Of note, both R375 and W376 are contained in the g-370-381 peptide identified by Podolnikova et al, 45 and the aIIb helix segment L151-D159 was contained in 1 of the 3 peptides that reacted most strongly with radiolabeled D-dimer reported by Podolnikova et al 38 Three out of the 13 clusters included structures in which residues contained in the g-316-322 region interact with aIIb, but because there were only 2 structures in each of these clusters, they were not pursued further.…”

Section: Molecular Modeling Of the Aiibb3 Headpiece-fibrinogen G-modumentioning

confidence: 99%

“…Regions of fibrinogen in addition to g-404-411 and regions of aIIbb3 in addition to the RGD binding pocket have been reported to affect ligand binding, 25,38,44,45 but there has been no detailed description of how any ancillary site on fibrinogen interacts with any ancillary region on aIIbb3. Specifically, potential ancillary sites have been identified in the fibrinogen g-module (g-148-411), including g-316-322 and g-370-381.…”

Section: Introductionmentioning

confidence: 99%

“…37 (3) The conversion of fibrinogen to fibrin exposes new epitopes for mAb's and thus potentially new interaction sites. 38 (4) Binding of fibrin to aIIbb3 has different physicochemical properties than binding to fibrinogen. 39 Identifying ancillary binding sites for fibrinogen and/or fibrin on aIIbb3 would provide a more comprehensive understanding of fibrinogen binding to platelets.…”

Section: Introductionmentioning

confidence: 99%

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αIIbβ3 binding to a fibrinogen fragment lacking the γ-chain dodecapeptide is activation dependent and EDTA inducible

Zafar

Shang

et al. 2017

Blood Advances

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Key Points• Activation of aIIbb3 is required for its ancillary site interactions with fibrinogen fragment D lacking the g-chain dodecapeptide ('D98').• EDTA can paradoxically induce normal aIIbb3 to interact with fibrinogen fragment 'D98.'Platelet integrin receptor aIIbb3 supports platelet aggregation by binding fibrinogen. The interaction between the fibrinogen C-terminal g-chain peptide composed of residues g-404-411 (GAKQAGDV) and the Arg-Gly-Asp (RGD) binding pocket on aIIbb3 is required for fibrinogen-mediated platelet aggregation, but data suggest that other ancillary binding sites on both fibrinogen and aIIbb3 may lead to higher-affinity fibrinogen binding and clot retraction. To identify additional sites, we analyzed the ability of platelets and cells expressing normal and mutant aIIbb3 to adhere to an immobilized fibrinogen plasmin fragment that lacks intact g-404-411 ('D98'). We found the following: (1) Activated, but not unactivated, platelets adhere well to immobilized 'D98.' (2) Cells expressing constitutively active aIIbb3 mutants, but not cells expressing normal aIIbb3 or aVb3, adhere well to 'D98.' Because molecular modeling and molecular dynamics simulations suggested that the aIIb L151-D159 helix may contribute to the interaction with 'D98,' we studied an aIIbb3 mutant in which the aIIb 148-166 loop was swapped with the corresponding aV loop; it failed to bind to fibrinogen or 'D98.' Our data support a model in which conformational changes in aIIbb3and/or fibrinogen after platelet activation and the interaction between g-404-411 and the RGD binding pocket make new ancillary sites available that support higher-affinity fibrinogen binding and clot retraction.

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Expanding the Mutation Spectrum Affecting αIIbβ3 Integrin in Glanzmann Thrombasthenia: Screening of theITGA2BandITGB3Genes in a Large International Cohort

et al. 2015

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We report the largest international study on Glanzmann thrombasthenia (GT), an inherited bleeding disorder where defects of the ITGA2B and ITGB3 genes cause quantitative or qualitative defects of the αIIbβ3 integrin, a key mediator of platelet aggregation. Sequencing of the coding regions and splice sites of both genes in members of 76 affected families identified 78 genetic variants (55 novel) suspected to cause GT. Four large deletions or duplications were found by quantitative real-time PCR. Families with mutations in either gene were indistinguishable in terms of bleeding severity that varied even among siblings. Families were grouped into type I and the rarer type II or variant forms with residual αIIbβ3 expression. Variant forms helped identify genes encoding proteins mediating integrin activation. Splicing defects and stop codons were common for both ITGA2B and ITGB3 and essentially led to a reduced or absent αIIbβ3 expression; included was a heterozygous c.1440-13_c.1440-1del in intron 14 of ITGA2B causing exon skipping in seven unrelated families. Molecular modeling revealed how many missense mutations induced subtle changes in αIIb and β3 domain structure across both subunits, thereby interfering with integrin maturation and/or function. Our study extends knowledge of GT and the pathophysiology of an integrin.

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The Interaction of Integrin αIIbβ3 with Fibrin Occurs through Multiple Binding Sites in the αIIb β-Propeller Domain

Cited by 49 publications

References 57 publications

Coated platelets function in platelet-dependent fibrin formation via integrin α _IIb β ₃ and transglutaminase factor XIII

Coated platelets function in platelet-dependent fibrin formation via integrin α _IIb β ₃ and transglutaminase factor XIII

αIIbβ3 binding to a fibrinogen fragment lacking the γ-chain dodecapeptide is activation dependent and EDTA inducible

Expanding the Mutation Spectrum Affecting αIIbβ3 Integrin in Glanzmann Thrombasthenia: Screening of theITGA2BandITGB3Genes in a Large International Cohort

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The Interaction of Integrin αIIbβ3 with Fibrin Occurs through Multiple Binding Sites in the αIIb β-Propeller Domain

Cited by 49 publications

References 57 publications

Coated platelets function in platelet-dependent fibrin formation via integrin α IIb β 3 and transglutaminase factor XIII

Coated platelets function in platelet-dependent fibrin formation via integrin α IIb β 3 and transglutaminase factor XIII

αIIbβ3 binding to a fibrinogen fragment lacking the γ-chain dodecapeptide is activation dependent and EDTA inducible

Expanding the Mutation Spectrum Affecting αIIbβ3 Integrin in Glanzmann Thrombasthenia: Screening of theITGA2BandITGB3Genes in a Large International Cohort

Contact Info

Product

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Coated platelets function in platelet-dependent fibrin formation via integrin α _IIb β ₃ and transglutaminase factor XIII

Coated platelets function in platelet-dependent fibrin formation via integrin α _IIb β ₃ and transglutaminase factor XIII