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Wang Y, Li R. Specific O-glycans in the mechanosensory domain of glycoprotein Ibα are important for its stability and function. Haematologica 2023; 108:2526-2530. [PMID: 36779596 PMCID: PMC10483358 DOI: 10.3324/haematol.2022.281979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/30/2023] [Indexed: 02/11/2023] Open
Abstract
Not available.
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Affiliation(s)
- Yingchun Wang
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322.
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2
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Dib F, Quéméner A, Bayart S, Boisseau P, Babuty A, Trossaërt M, Sigaud M, Ternisien C, Drillaud N, Eveillard M, Guillet B, Béné MC, Fouassier M. Biological, clinical features and modelling of heterozygous variants of glycoprotein Ib platelet subunit alpha (GP1BA) and glycoprotein Ib platelet subunit beta (GP1BB) genes responsible for constitutional thrombocytopenia. Br J Haematol 2022; 199:744-753. [PMID: 36173017 DOI: 10.1111/bjh.18462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 11/28/2022]
Abstract
Constitutional thrombocytopenias are rare disorders, often difficult to discriminate from acquired thrombocytopenias. More than 80 genes have been described as being at the origin of these diseases. Among them, several variants of the glycoprotein Ib platelet subunit alpha (GP1BA) and glycoprotein Ib platelet subunit beta (GP1BB) genes, coding for the GpIb-IX-V glycoprotein complex, have been reported in the literature. The study reported here aimed at describing newly identified monoallelic anomalies affecting the GP1BA and GP1BB genes on a clinical, biological and molecular level. In a cohort of nine patients with macrothrombocytopenia, eight heterozygous variants of the GP1BA or GP1BB genes were identified. Five of them had never been described in the heterozygous state. Computer modelling disclosed structure/function relationships of these five variants.
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Affiliation(s)
- Fatema Dib
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France
| | - Agnès Quéméner
- Nantes Université, Inserm UMR 1307, CNRS UMR 6075, Université d'Angers, CRCI2NA, Nantes, France
| | | | - Pierre Boisseau
- Service de Génétique Médicale, CHU de Nantes, Nantes, France
| | - Antoine Babuty
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,CRC-MH, CHU de Nantes, Nantes, France
| | - Marc Trossaërt
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,CRC-MH, CHU de Nantes, Nantes, France
| | - Marianne Sigaud
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,CRC-MH, CHU de Nantes, Nantes, France
| | - Catherine Ternisien
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,CRC-MH, CHU de Nantes, Nantes, France
| | - Nicolas Drillaud
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,CRC-MH, CHU de Nantes, Nantes, France
| | - Marion Eveillard
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,Nantes Université, Inserm UMR 1307, CNRS UMR 6075, Université d'Angers, CRCI2NA, Nantes, France
| | - Benoit Guillet
- CRC-MH, CHU de Rennes, Rennes, France.,Univ Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, Rennes, France
| | - Marie C Béné
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,Nantes Université, Inserm UMR 1307, CNRS UMR 6075, Université d'Angers, CRCI2NA, Nantes, France
| | - Marc Fouassier
- Service d'Hématologie Biologique, CHU de Nantes, Nantes, France.,CRC-MH, CHU de Nantes, Nantes, France
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Bendas G, Schlesinger M. The GPIb-IX complex on platelets: insight into its novel physiological functions affecting immune surveillance, hepatic thrombopoietin generation, platelet clearance and its relevance for cancer development and metastasis. Exp Hematol Oncol 2022; 11:19. [PMID: 35366951 PMCID: PMC8976409 DOI: 10.1186/s40164-022-00273-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/19/2022] [Indexed: 12/13/2022] Open
Abstract
The glycoprotein (GP) Ib-IX complex is a platelet receptor that mediates the initial interaction with subendothelial von Willebrand factor (VWF) causing platelet arrest at sites of vascular injury even under conditions of high shear. GPIb-IX dysfunction or deficiency is the reason for the rare but severe Bernard-Soulier syndrome (BSS), a congenital bleeding disorder. Although knowledge on GPIb-IX structure, its basic functions, ligands, and intracellular signaling cascades have been well established, several advances in GPIb-IX biology have been made in the recent years. Thus, two mechanosensitive domains and a trigger sequence in GPIb were characterized and its role as a thrombin receptor was deciphered. Furthermore, it became clear that GPIb-IX is involved in the regulation of platelet production, clearance and thrombopoietin secretion. GPIb is deemed to contribute to liver cancer development and metastasis. This review recapitulates these novel findings highlighting GPIb-IX in its multiple functions as a key for immune regulation, host defense, and liver cancer development.
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Affiliation(s)
- Gerd Bendas
- Department of Pharmacy, Rheinische Friedrich-Wilhelms-University Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Martin Schlesinger
- Department of Pharmacy, Rheinische Friedrich-Wilhelms-University Bonn, An der Immenburg 4, 53121, Bonn, Germany. .,Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany.
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A Novel Mutation in GP1BB Reveals the Role of the Cytoplasmic Domain of GPIbβ in the Pathophysiology of Bernard-Soulier Syndrome and GPIb-IX Complex Assembly. Int J Mol Sci 2021; 22:ijms221910190. [PMID: 34638529 PMCID: PMC8508601 DOI: 10.3390/ijms221910190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 12/24/2022] Open
Abstract
Bernard-Soulier syndrome (BSS) is an autosomal-recessive bleeding disorder caused by biallelic variants in the GP1BA, GP1BB, and GP9 genes encoding the subunits GPIbα, GPIbβ, and GPIX of the GPIb-IX complex. Pathogenic variants usually affect the extracellular or transmembrane domains of the receptor subunits. We investigated a family with BSS caused by the homozygous c.528_550del (p.Arg177Serfs*124) variant in GP1BB, which is the first mutation ever identified that affects the cytoplasmic domain of GPIbβ. The loss of the intracytoplasmic tail of GPIbβ results in a mild form of BSS, characterized by only a moderate reduction of the GPIb-IX complex expression and mild or absent bleeding tendency. The variant induces a decrease of the total platelet expression of GPIbβ; however, all of the mutant subunit expressed in platelets is correctly assembled into the GPIb-IX complex in the plasma membrane, indicating that the cytoplasmic domain of GPIbβ is not involved in assembly and trafficking of the GPIb-IX receptor. Finally, the c.528_550del mutation exerts a dominant effect and causes mild macrothrombocytopenia in heterozygous individuals, as also demonstrated by the investigation of a second unrelated pedigree. The study of this novel GP1BB variant provides new information on pathophysiology of BSS and the assembly mechanisms of the GPIb-IX receptor.
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Quach ME, Li R. Structure-function of platelet glycoprotein Ib-IX. J Thromb Haemost 2020; 18:3131-3141. [PMID: 32735697 PMCID: PMC7854888 DOI: 10.1111/jth.15035] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 12/20/2022]
Abstract
The glycoprotein (GP)Ib-IX receptor complex plays a critical role in platelet physiology and pathology. Its interaction with von Willebrand factor (VWF) on the subendothelial matrix instigates platelet arrest at the site of vascular injury and is vital to primary hemostasis. Its reception to other ligands and counter-receptors in the bloodstream also contribute to various processes of platelet biology that are still being discovered. While its basic composition and its link to congenital bleeding disorders were well documented and firmly established more than 25 years ago, recent years have witnessed critical advances in the organization, dynamics, activation, regulation, and functions of the GPIb-IX complex. This review summarizes important findings and identifies questions that remain about this unique platelet mechanoreceptor complex.
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Affiliation(s)
- M Edward Quach
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, USA
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