1
|
Ferrari S, Regazzo D, Cerbo A, Cortella I, Bertomoro A, Simioni P. The compound pathogenic effects of a homozygous frameshift variant in the transmembrane region of GP9, causing Bernard-Soulier syndrome, with a missense variant in GP1BB. Br J Haematol 2024. [PMID: 38923496 DOI: 10.1111/bjh.19593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024]
Affiliation(s)
- Silvia Ferrari
- Department of Medicine - DIMED, Padova University Hospital, Padova, Italy
| | - Daniela Regazzo
- Department of Medicine - DIMED, Padova University Hospital, Padova, Italy
| | - Anna Cerbo
- Department of Medicine - DIMED, Padova University Hospital, Padova, Italy
| | - Irene Cortella
- Department of Medicine - DIMED, Padova University Hospital, Padova, Italy
| | | | - Paolo Simioni
- Department of Medicine - DIMED, Padova University Hospital, Padova, Italy
| |
Collapse
|
2
|
Martinez-Navajas G, Ceron-Hernandez J, Simon I, Lupiañez P, Diaz-McLynn S, Perales S, Modlich U, Guerrero JA, Martin F, Sevivas T, Lozano ML, Rivera J, Ramos-Mejia V, Tersteeg C, Real PJ. Lentiviral gene therapy reverts GPIX expression and phenotype in Bernard-Soulier syndrome type C. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 33:75-92. [PMID: 37416759 PMCID: PMC10320622 DOI: 10.1016/j.omtn.2023.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 06/08/2023] [Indexed: 07/08/2023]
Abstract
Bernard-Soulier syndrome (BSS) is a rare congenital disease characterized by macrothrombocytopenia and frequent bleeding. It is caused by pathogenic variants in three genes (GP1BA, GP1BB, or GP9) that encode for the GPIbα, GPIbβ, and GPIX subunits of the GPIb-V-IX complex, the main platelet surface receptor for von Willebrand factor, being essential for platelet adhesion and aggregation. According to the affected gene, we distinguish BSS type A1 (GP1BA), type B (GP1BB), or type C (GP9). Pathogenic variants in these genes cause absent, incomplete, or dysfunctional GPIb-V-IX receptor and, consequently, a hemorrhagic phenotype. Using gene-editing tools, we generated knockout (KO) human cellular models that helped us to better understand GPIb-V-IX complex assembly. Furthermore, we developed novel lentiviral vectors capable of correcting GPIX expression, localization, and functionality in human GP9-KO megakaryoblastic cell lines. Generated GP9-KO induced pluripotent stem cells produced platelets that recapitulated the BSS phenotype: absence of GPIX on the membrane surface and large size. Importantly, gene therapy tools reverted both characteristics. Finally, hematopoietic stem cells from two unrelated BSS type C patients were transduced with the gene therapy vectors and differentiated to produce GPIX-expressing megakaryocytes and platelets with a reduced size. These results demonstrate the potential of lentiviral-based gene therapy to rescue BSS type C.
Collapse
Affiliation(s)
- Gonzalo Martinez-Navajas
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
- University of Granada, Department of Biochemistry and Molecular Biology I, Faculty of Science, Avenida Fuentenueva S/n, 18071 Granada, Spain
| | - Jorge Ceron-Hernandez
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
- University of Granada, Department of Biochemistry and Molecular Biology I, Faculty of Science, Avenida Fuentenueva S/n, 18071 Granada, Spain
| | - Iris Simon
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
- University of Granada, Department of Biochemistry and Molecular Biology I, Faculty of Science, Avenida Fuentenueva S/n, 18071 Granada, Spain
| | - Pablo Lupiañez
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
- University of Granada, Department of Biochemistry and Molecular Biology I, Faculty of Science, Avenida Fuentenueva S/n, 18071 Granada, Spain
| | - Sofia Diaz-McLynn
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
| | - Sonia Perales
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
- University of Granada, Department of Biochemistry and Molecular Biology I, Faculty of Science, Avenida Fuentenueva S/n, 18071 Granada, Spain
- Instituto de Investigación Biosanitaria Ibs.GRANADA, Granada, Spain
| | - Ute Modlich
- Department of Gene and Cell Therapy, Institute of Regenerative Medicine, University of Zürich, Wagistrasse 12, 8952 Schlieren-Zürich, Switzerland
| | - Jose A. Guerrero
- Department of Haematology, University of Cambridge, Cambridge, UK
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
| | - Francisco Martin
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
- University of Granada, Department of Biochemistry and Molecular Biology III and Immunology, Faculty of Medicine, Avenida Ilustracion S/n, 18016 Granada, Spain
| | - Teresa Sevivas
- Serviço de Sangue, Medicina Transfusional e Imunohemoterapia Do Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Maria L. Lozano
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Pascual Parrilla, CIBERER-ISCIII, U765 Murcia, Spain
| | - Jose Rivera
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Pascual Parrilla, CIBERER-ISCIII, U765 Murcia, Spain
- Grupo Español de Alteraciones Plaquetarias Congénitas (GEAPC), Madrid, Spain
| | - Veronica Ramos-Mejia
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
| | - Claudia Tersteeg
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Pedro J. Real
- GENyO, Pfizer-Universidad de Granada-Junta de Andalucia Centre for Genomics and Oncological Research, PTS, Granada, Avenida de la Ilustracion 114, 18016 Granada, Spain
- University of Granada, Department of Biochemistry and Molecular Biology I, Faculty of Science, Avenida Fuentenueva S/n, 18071 Granada, Spain
- Instituto de Investigación Biosanitaria Ibs.GRANADA, Granada, Spain
| |
Collapse
|
3
|
Sun S, Qiao B, Han Y, Wang B, Wei S, Chen Y. Posttranslational modifications of platelet adhesion receptors. Pharmacol Res 2022; 183:106413. [PMID: 36007773 DOI: 10.1016/j.phrs.2022.106413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/11/2022] [Accepted: 08/19/2022] [Indexed: 10/15/2022]
Abstract
Platelets play a key role in normal hemostasis, whereas pathological platelet adhesion is involved in various cardiovascular events. The underlying cause in cardiovascular events involves plaque rupture leading to subsequent platelet adhesion, activation, release, and eventual thrombosis. Traditional antithrombotic drugs often target the signal transduction process of platelet adhesion receptors by influencing the synthesis of some key molecules, and their effects are limited. Posttranslational modifications (PTMs) of platelet adhesion receptors increase the functional diversity of the receptors and affect platelet physiological and pathological processes. Antithrombotic drugs targeting PTMs of platelet adhesion receptors may represent a new therapeutic idea. In this review, various PTMs, including phosphorylation, glycosylation, ubiquitination, nitrosylation, methylation, lipidation, and proteolysis, of three platelet adhesion receptors, glycoprotein Ib-IX-V (GPIb-IX-V), glycoprotein VI (GPVI), and integrin αIIbβ3, are reviewed. It is important to comprehensively understand the PTMs process of platelet adhesion receptors.
Collapse
Affiliation(s)
- Shukun Sun
- Department of Emergency and Chest Pain Center, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Clinical Research Center for Emergency and Critical Care Medicine of Shandong Province, Institute of Emergency and Critical Care Medicine of Shandong University, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Key Laboratory of Cardiopulmonary-Cerebral Resuscitation Research of Shandong Province, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese Ministry of Health and Chinese Academy of Medical Sciences, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Bao Qiao
- Department of Emergency and Chest Pain Center, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Clinical Research Center for Emergency and Critical Care Medicine of Shandong Province, Institute of Emergency and Critical Care Medicine of Shandong University, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Key Laboratory of Cardiopulmonary-Cerebral Resuscitation Research of Shandong Province, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese Ministry of Health and Chinese Academy of Medical Sciences, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Yu Han
- Department of Emergency and Chest Pain Center, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Clinical Research Center for Emergency and Critical Care Medicine of Shandong Province, Institute of Emergency and Critical Care Medicine of Shandong University, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Key Laboratory of Cardiopulmonary-Cerebral Resuscitation Research of Shandong Province, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese Ministry of Health and Chinese Academy of Medical Sciences, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Bailu Wang
- Clinical Trial Center, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Shujian Wei
- Department of Emergency and Chest Pain Center, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Clinical Research Center for Emergency and Critical Care Medicine of Shandong Province, Institute of Emergency and Critical Care Medicine of Shandong University, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Key Laboratory of Cardiopulmonary-Cerebral Resuscitation Research of Shandong Province, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese Ministry of Health and Chinese Academy of Medical Sciences, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China.
| | - Yuguo Chen
- Department of Emergency and Chest Pain Center, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Clinical Research Center for Emergency and Critical Care Medicine of Shandong Province, Institute of Emergency and Critical Care Medicine of Shandong University, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Key Laboratory of Emergency and Critical Care Medicine of Shandong Province, Key Laboratory of Cardiopulmonary-Cerebral Resuscitation Research of Shandong Province, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese Ministry of Health and Chinese Academy of Medical Sciences, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China.
| |
Collapse
|
4
|
Martins Castanheira N, Spanhofer AK, Wiener S, Bobe S, Schillers H. Uptake of platelets by cancer cells and recycling of the platelet protein CD42a. J Thromb Haemost 2022; 20:170-181. [PMID: 34592045 DOI: 10.1111/jth.15543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND It is well accepted that the bidirectional crosstalk between platelets and cancer cells promotes tumorigenesis and metastasis. In an early step, cancer cells trigger platelet granule and extracellular vesicle release that is needed to facilitate cancer cell survival in circulation. OBJECTIVES To discover the early crosstalk of cancer cells and platelets. METHODS Cancer cells were incubated with freshly isolated and stained human platelets. Confocal laser scanning microscopy and flow cytometry was used to visualize and to quantify platelet uptake and the membrane presence of CD42 on cancer cells. Dyngo4a was used to test if platelet uptake is a dynamin-dependent process. RESULTS We found a dynamin-dependent uptake of platelets by cancer cells. This is followed by the recycling of the platelet-specific protein CD42a and its incorporation into cancer cells' plasma membrane, which is not a result of platelet RNA transfer by platelet-derived microparticles and exosomes. Time course of platelet uptake follows a sigmoid function revealing that 50% of the cancer cells are positive for platelets after approximately 38 min. Platelet uptake was observed for the tested cancerous cells (A549, MCF-7, and MV3) but not for the non-cancerous cell line 16HBE14o-. CONCLUSIONS Our results demonstrate that cancer cells hijack platelets by phagocytosis and recycling of platelet membrane proteins. The uptake of platelets has additional advantages for cancer cells: access to the entire and undiluted platelet proteome, transcriptome, and secretome. These novel findings will allow further mechanistic elucidation and thus help us gain deeper insights into platelet-assisted hematogenous metastasis.
Collapse
Affiliation(s)
| | - Anna K Spanhofer
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Sebastian Wiener
- Institute of Physiology II, University of Muenster, Muenster, Germany
| | - Stefanie Bobe
- Institute of Physiology II, University of Muenster, Muenster, Germany
- Gerhard-Domagk-Institute of Pathology, University Hospital Muenster, Muenster, Germany
| | - Hermann Schillers
- Institute of Physiology II, University of Muenster, Muenster, Germany
| |
Collapse
|
5
|
Essential role of zyxin in platelet biogenesis and glycoprotein Ib-IX surface expression. Cell Death Dis 2021; 12:955. [PMID: 34657146 PMCID: PMC8520529 DOI: 10.1038/s41419-021-04246-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 09/15/2021] [Accepted: 09/28/2021] [Indexed: 12/17/2022]
Abstract
Platelets are generated from the cytoplasm of megakaryocytes (MKs) via actin cytoskeleton reorganization. Zyxin is a focal adhesion protein and wildly expressed in eukaryotes to regulate actin remodeling. Zyxin is upregulated during megakaryocytic differentiation; however, the role of zyxin in thrombopoiesis is unknown. Here we show that zyxin ablation results in profound macrothrombocytopenia. Platelet lifespan and thrombopoietin level were comparable between wild-type and zyxin-deficient mice, but MK maturation, demarcation membrane system formation, and proplatelet generation were obviously impaired in the absence of zyxin. Differential proteomic analysis of proteins associated with macrothrombocytopenia revealed that glycoprotein (GP) Ib-IX was significantly reduced in zyxin-deficient platelets. Moreover, GPIb-IX surface level was decreased in zyxin-deficient MKs. Knockdown of zyxin in a human megakaryocytic cell line resulted in GPIbα degradation by lysosomes leading to the reduction of GPIb-IX surface level. We further found that zyxin was colocalized with vasodilator-stimulated phosphoprotein (VASP), and loss of zyxin caused diffuse distribution of VASP and actin cytoskeleton disorganization in both platelets and MKs. Reconstitution of zyxin with VASP binding site in zyxin-deficient hematopoietic progenitor cell-derived MKs restored GPIb-IX surface expression and proplatelet generation. Taken together, our findings identify zyxin as a regulator of platelet biogenesis and GPIb-IX surface expression through VASP-mediated cytoskeleton reorganization, suggesting possible pathogenesis of macrothrombocytopenia.
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Tao Y, Gan C, Zhang X, Liu L, Zakas PM, Doering CB, Mo X, Li R. Unaccompanied mechanosensory domain mediates low expression of glycoprotein Ibα: implications for Bernard-Soulier syndrome. J Thromb Haemost 2020; 18:510-517. [PMID: 31749281 PMCID: PMC7592420 DOI: 10.1111/jth.14684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/18/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Disruption of protein folding or inter-subunit interactions in the platelet glycoprotein (GP)Ib-IX complex leads to its abnormally low expression in the plasma membrane, the hallmark of Bernard-Soulier syndrome (BSS). OBJECTIVE To discover the molecular mechanism by which GPIbα in the absence of GPIbβ and GPIX subunits is targeted for rapid degradation. METHOD The expression of GPIbα mutants with deletion or replacement of various domains were measured in transiently transfected Chinese hamster ovary cells. RESULTS We report evidence to suggest that induction of the unfolded protein response by the unaccompanied mechanosensory domain (MSD) is a major factor for intracellular degradation and low expression of GPIbα. Removal of the MSD produced the first GPIbα variant that, even in the absence of GPIbβ and GPIX, expressed at a level comparable to that of wild-type GPIbα in the GPIb-IX complex, while retaining its native ligand-binding activity. CONCLUSION Our finding has important implications on the molecular pathogenesis of BSS and the function of the GPIb-IX complex.
Collapse
Affiliation(s)
- Yue Tao
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Chi Gan
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Xiaoqin Zhang
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Lanbo Liu
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Philip M. Zakas
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Christopher B. Doering
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Xi Mo
- Pediatric Translational Medicine Institute, Shanghai Children’s Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Renhao Li
- Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| |
Collapse
|
8
|
Minkov M, Zeitlhofer P, Zoubek A, Kager L, Panzer S, Haas OA. Novel Compound Heterozygous Mutations in Two Families With Bernard-Soulier Syndrome. Front Pediatr 2020; 8:589812. [PMID: 33553065 PMCID: PMC7864212 DOI: 10.3389/fped.2020.589812] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/14/2020] [Indexed: 12/03/2022] Open
Abstract
Background: Bernard-Soulier Syndrome (BSS) is a rare autosomal recessive bleeding disorder with large platelets and thrombocytopenia. It is caused by homozygous or compound heterozygous mutations in the GP1BA, GP1BB, or GP9 genes, which together encode the platelet surface receptor glycoprotein complex GPIb-IX-V. Objectives: We report two novel heterozygous mutations in the GP1BA and the GP9 genes, respectively. Patients/Methods: We analyzed the platelet glycoprotein expression by flow cytometry and screened the relevant genes for responsible mutations in two unrelated families. Results: Flow cytometric analyses revealed the absence of CD42a (GPIX) and CD42b (GPIb) on the platelets in the two affected siblings of family 1 and a significantly reduced expression of CD42b (GPIb) in the patient of family 2. In the two siblings, we identified a known frameshift (c.1601_1602delAT) and a novel nonsense mutation (c.1036C>T) in the GP1BA gene that abrogated the production of GP1bα. In the other patient, we found a novel missense mutation (c.112T>C) that was co-inherited with a common one (c.182A>G) in the GP9 gene, respectively. All analyzed heterozygous carriers were asymptomatic and had a normal GPIb-IX-V expression. Conclusions: The two novel GP1BA and GP9 mutations reported herein increment the number of causative genetic defects in BSS.
Collapse
Affiliation(s)
- Milen Minkov
- Department of Pediatrics, Clinic Floridsdorf, Vienna, Austria.,Faculty of Medicine, Sigmund Freud University, Vienna, Austria.,St. Anna Children's Hospital, Department of Pediatric Hematology/Oncology, University Clinic of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Petra Zeitlhofer
- Labdia GmbH, St. Anna Kinderkrebsforschung GmbH, Vienna, Austria
| | - Andreas Zoubek
- Private Practice for General Pediatrics and Pediatric Hematology/Oncology, Maria Enzersdorf, Austria
| | - Leo Kager
- St. Anna Children's Hospital, Department of Pediatric Hematology/Oncology, University Clinic of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Simon Panzer
- Department of Blood Group Serology and Transfusion Medicine, Medical University Vienna, Vienna, Austria
| | - Oskar A Haas
- St. Anna Children's Hospital, Department of Pediatric Hematology/Oncology, University Clinic of Pediatrics, Medical University of Vienna, Vienna, Austria.,Labdia GmbH, St. Anna Kinderkrebsforschung GmbH, Vienna, Austria
| |
Collapse
|
9
|
Gentilini F, Turba ME, Giancola F, Chiocchetti R, Bernardini C, Dajbychova M, Jagannathan V, Drögemüller M, Drögemüller C. A large deletion in the GP9 gene in Cocker Spaniel dogs with Bernard-Soulier syndrome. PLoS One 2019; 14:e0220625. [PMID: 31484196 PMCID: PMC6726462 DOI: 10.1371/journal.pone.0220625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/20/2019] [Indexed: 12/16/2022] Open
Abstract
Inherited bleeding disorders including abnormalities of platelet number and function rarely occur in a variety of dog breeds, but are probably underdiagnosed. Genetically characterized canine forms of platelet disorders provide valuable large animal models for understanding similar platelet disorders in people. Breed-specific disease associated genetic variants in only eight different genes are known to cause intrinsic platelet disorders in dogs. However, the causative genetic variant in many dog breeds has until now remained unknown. Four cases of a mild to severe bleeding disorder in Cocker Spaniel dogs are herein presented. The affected dogs showed a platelet adhesion defect characterized by macrothrombocytopenia with variable platelet counts resembling human Bernard-Soulier syndrome (BSS). Furthermore, the lack of functional GPIb-IX-V was demonstrated by immunocytochemistry. Whole genome sequencing of one affected dog and visual inspection of the candidate genes identified a deletion in the glycoprotein IX platelet (GP9) gene. The GP9 gene encodes a subunit of a platelet surface membrane glycoprotein complex; this functions as a receptor for von Willebrand factor, which initiates the maintenance of hemostasis after injury. Variants in human GP9 are associated with Bernard-Soulier syndrome, type C. The deletion spanned 2460 bp, and included a significant part of the single coding exon of the canine GP9 gene on dog chromosome 20. The variant results in a frameshift and premature stop codon which is predicted to truncate almost two-thirds of the encoded protein. PCR-based genotyping confirmed recessive inheritance. The homozygous variant genotype seen in affected dogs did not occur in 98 control Cocker Spaniels. Thus, it was concluded that the structural variant identified in the GP9 gene was most likely causative for the BSS-phenotype in the dogs examined. These findings provide the first large animal GP9 model for this group of inherited platelet disorders and greatly facilitate the diagnosis and identification of affected and/or normal carriers in Cocker Spaniels.
Collapse
Affiliation(s)
- Fabio Gentilini
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
- * E-mail:
| | | | - Fiorella Giancola
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Roberto Chiocchetti
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Chiara Bernardini
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | | | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| |
Collapse
|
10
|
Cattaneo M. Inherited Disorders of Platelet Function. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00048-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
11
|
The Glycoprotein Ib-IX-V Complex. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00010-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
|
12
|
Affiliation(s)
- Markus Bender
- Department of Experimental Biomedicine, University of Würzburg, University Hospital and Rudolf Virchow Center, Würzburg, Germany
| | - David Stegner
- Department of Experimental Biomedicine, University of Würzburg, University Hospital and Rudolf Virchow Center, Würzburg, Germany
| | - Bernhard Nieswandt
- Department of Experimental Biomedicine, University of Würzburg, University Hospital and Rudolf Virchow Center, Würzburg, Germany
| |
Collapse
|
13
|
Signaling-mediated cooperativity between glycoprotein Ib-IX and protease-activated receptors in thrombin-induced platelet activation. Blood 2015; 127:626-36. [PMID: 26585954 DOI: 10.1182/blood-2015-04-638387] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 11/12/2015] [Indexed: 11/20/2022] Open
Abstract
Thrombin-induced cellular response in platelets not only requires protease-activated receptors (PARs), but also involves another thrombin receptor, the glycoprotein Ib-IX complex (GPIb-IX). It remains controversial how thrombin binding to GPIb-IX stimulates platelet responses. It was proposed that GPIb-IX serves as a dock that facilitates thrombin cleavage of protease-activated receptors, but there are also reports suggesting that thrombin binding to GPIb-IX induces platelet activation independent of PARs. Here we show that GPIb is neither a passive thrombin dock nor a PAR-independent signaling receptor. We demonstrate a novel signaling-mediated cooperativity between PARs and GPIb-IX. Low-dose thrombin-induced PAR-dependent cell responses require the cooperativity of GPIb-IX signaling, and conversely, thrombin-induced GPIb-IX signaling requires cooperativity of PARs. This mutually dependent cooperativity requires a GPIb-IX-specific 14-3-3-Rac1-LIMK1 signaling pathway, and activation of this pathway also requires PAR signaling. The cooperativity between GPIb-IX signaling and PAR signaling thus drives platelet activation at low concentrations of thrombin, which are important for in vivo thrombosis.
Collapse
|
14
|
Identification of a juxtamembrane mechanosensitive domain in the platelet mechanosensor glycoprotein Ib-IX complex. Blood 2014; 125:562-9. [PMID: 25359992 DOI: 10.1182/blood-2014-07-589507] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
How glycoprotein (GP)Ib-IX complex on the platelet surface senses the blood flow through its binding to the plasma protein von Willebrand factor (VWF) and transmits a signal into the platelet remains unclear. Here we show that optical tweezer-controlled pulling of the A1 domain of VWF (VWF-A1) on GPIb-IX captured by its cytoplasmic domain induced unfolding of a hitherto unidentified structural domain before the dissociation of VWF-A1 from GPIb-IX. Additional studies using recombinant proteins and mutant complexes confirmed its existence in GPIb-IX and enabled localization of this quasi-stable mechanosensitive domain of ∼60 residues between the macroglycopeptide region and the transmembrane helix of the GPIbα subunit. These results suggest that VWF-mediated pulling under fluid shear induces unfolding of the mechanosensitive domain in GPIb-IX, which may possibly contribute to platelet mechanosensing and/or shear resistance of VWF-platelet interaction. The identification of the mechanosensitive domain in GPIb-IX has significant implications for the pathogenesis and treatment of related blood diseases.
Collapse
|
15
|
Zhou L, Yang W, Li R. Analysis of inter-subunit contacts reveals the structural malleability of extracellular domains in platelet glycoprotein Ib-IX complex. J Thromb Haemost 2014; 12:82-9. [PMID: 24406065 PMCID: PMC4137403 DOI: 10.1111/jth.12437] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND The glycoprotein (GP)Ib-IX complex is critical to hemostasis and thrombosis. Its proper assembly is closely correlated with its surface expression level and requires cooperative interactions among extracellular and transmembrane domains of Ibα, Ibβ and IX subunits. Two interfaces have been previously identified between the extracellular domains of Ibβ and IX. OBJECTIVE To understand how extracellular domains interact in GPIb-IX. METHODS The Ibβ extracellular domain (IbβE ) or the IX counterpart (IXE ) in GPIb-IX was replaced with a well-folded IbβE /IXE chimera called IbβEabc , and the effect of domain replacement on assembly and expression of the receptor complex in transiently transfected Chinese hamster ovary cells was analyzed. RESULTS Replacing IXE with IbβEabc in GPIb-IX retained interface 1 but not interface 2 between the extracellular domains. While this domain replacement preserved complex integrity, the expression levels of Ibβ and Ibα were significantly reduced. Additional domain replacement with IbβEabc or IbβE in GPIb-IX produced the complex at disparate expression levels that cannot be simply explained by two separate interfaces. In particular, when IbβE in GPIb-IX was replaced by IbβEabc , Ibα and IX were expressed at approximately 70% of the wild-type level. Their levels were not reduced when IXE was changed further to IbβE . CONCLUSIONS Our results demonstrate the importance of the association between Ibβ and IX extracellular domains for complex assembly and efficient expression, and provide evidence for the structural malleability of these domains that may accommodate and propagate conformational changes therein.
Collapse
Affiliation(s)
- L Zhou
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, Atlanta, GA, USA
| | | | | |
Collapse
|
16
|
Novel genetic abnormalities in Bernard-Soulier syndrome in India. Ann Hematol 2013; 93:381-4. [DOI: 10.1007/s00277-013-1895-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/25/2013] [Indexed: 11/27/2022]
|
17
|
|
18
|
Li R, Emsley J. The organizing principle of the platelet glycoprotein Ib-IX-V complex. J Thromb Haemost 2013; 11:605-14. [PMID: 23336709 PMCID: PMC3696474 DOI: 10.1111/jth.12144] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 01/17/2013] [Indexed: 11/28/2022]
Abstract
The glycoprotein (GP)Ib-IX-V complex is the platelet receptor for von Willebrand factor and many other molecules that are critically involved in hemostasis and thrombosis. The lack of functional GPIb-IX-V complexes on the platelet surface is the cause of Bernard-Soulier syndrome, a rare hereditary bleeding disorder that is also associated with macrothrombocytopenia. GPIb-IX-V contains GPIbα, GPIbβ, GPIX and GPV subunits, all of which are type I transmembrane proteins containing leucine-rich repeat domains. Although all of the subunits were identified decades ago, not until recently did the mechanism of complex assembly begin to emerge from a systematic characterization of inter-subunit interactions. This review summarizes the forces driving the assembly of GPIb-IX-V, discusses their implications for the pathogenesis of Bernard-Soulier syndrome, and identifies questions that remain about the structure and organization of GPIb-IX-V.
Collapse
Affiliation(s)
- R Li
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, Atlanta, GA30322, USA.
| | | |
Collapse
|
19
|
Cattaneo M. Congenital Disorders of Platelet Function. Platelets 2013. [DOI: 10.1016/b978-0-12-387837-3.00050-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
20
|
Heat-shock protein gp96/grp94 is an essential chaperone for the platelet glycoprotein Ib-IX-V complex. Blood 2011; 117:7136-44. [PMID: 21576699 DOI: 10.1182/blood-2011-01-330464] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The platelet glycoprotein Ib-IX-V complex (GPIb-IX-IV) is the receptor for VWF and is responsible for VWF-mediated platelet activation and aggregation. Loss of the GPIb-IX-V complex is pathogenic for Bernard-soulier Syndrome (BSS), which is characterized by macrothrombocytopenia and impaired platelet function. It remains unclear how the GPIb-IX-V complex is assembled and whether there is a role for a specific molecular chaperone in the process. In the present study, we report that the assembly of the GPIb-IX-V complex depends critically on a molecular chaperone in the endoplasmic reticulum (ER): gp96 (also known as grp94 and HSP90b1). gp96/grp94 deletion in the murine hematopoietic system results in thrombocytopenia, prolonged bleeding time, and giant platelets that are clinically indistinguishable from human BSS. Loss of gp96/grp94 in vivo and in vitro leads to the concomitant reduction in GPIb-IX complex expression due to ER-associated degradation. We further demonstrate that gp96/grp94 binds selectively to the GPIX subunit, but not to gpIbα or gpIbβ. Therefore, we identify the platelet GPIX subunit of the GPIb-IX-V complex as an obligate and novel client of gp96/grp94.
Collapse
|
21
|
Shen L, Shen D, Zhu R, Zhu M, Lu F, Qin Y, Fan H. Expression of platelet membrane glycoprotein Ib/IX/V complex, a receptor of thrombin, in patients with hemorrhagic thrombopathy. JOURNAL OF HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY. MEDICAL SCIENCES = HUA ZHONG KE JI DA XUE XUE BAO. YI XUE YING DE WEN BAN = HUAZHONG KEJI DAXUE XUEBAO. YIXUE YINGDEWEN BAN 2008; 28:657-659. [PMID: 19107360 DOI: 10.1007/s11596-008-0609-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Indexed: 05/27/2023]
Abstract
To investigate the role of platelet membrane glycoprotein (GP) Ib/IX/V complex and its subunit GP Ibalpha in patients with hemorrhagic thrombopathy (HT), the expressions of GP Ib/IX/V complex and GP Ibalpha, defined as mean fluorescence intensity (MFI), were assessed by flow cytometry. The maximum aggregation of platelet was determined by turbidity method. These indicators were compared among 68 HT patients with the presenting complaint of hemorrhage, 33 well-controlled HT patients and 32 normal healthy subjects. The results showed that the MFI of GP Ib/IX/V complex and GP Ibalpha was markedly lower in HT patients with current hemorrhage than that in the healthy subjects, with difference being statistically significant (P<0.05). There was no significant difference in the expressions of GP Ib/IX/V complex and GP Ibalpha between well-controlled HT patients and normal healthy subjects (P>0.05). It was concluded that the expression of GP Ib/IX/V complex, the receptor of thrombin and von Willebrand factor, was down-regulated in HT patients with current hemorrhage, which might result in the dysfunction of platelet aggregation and recurrence of HT.
Collapse
Affiliation(s)
- Lin Shen
- Department of Integrated Traditional Chinese and Western Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | | | | | | | | | | | | |
Collapse
|
22
|
Li Y, Lu J, Prochownik EV. Modularity of the oncoprotein-like properties of platelet glycoprotein Ibalpha. J Biol Chem 2008; 284:1410-8. [PMID: 19017648 DOI: 10.1074/jbc.m806222200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycoprotein Ib alpha (GpIbalpha), a trans-membrane glycoprotein, is expressed on the surface of megakaryocytes and platelets, where, in association with glycoprotein Ib beta, glycoprotein V, and glycoprotein IX, it normally forms the von Willebrand factor receptor (vWFR). A fully functional vWFR is necessary for platelet attachment, aggregation, and activation and has also been shown to regulate megakaryocyte ploidy. We have recently shown that the gene encoding GpIbalpha is a transcriptional target for the c-Myc oncoprotein and is more widely expressed than previously thought, with particularly high levels occurring in transformed cells. Indeed, GpIbalpha can substitute for c-Myc in promoting growth, transformation, and genomic instability. In the current work, we have demonstrated that, despite the promiscuous expression of GpIbalpha, other vWFR subunits remain largely restricted to megakaryocytes. We have characterized a panel of GpIbalpha mutants and shown that some regions of the protein essential for vWFR activity are not necessary for c-Myc-like functions. Specifically, the six C-terminal amino acids of the cytoplasmic domain, which mediate vWFR signaling, are entirely dispensible for the c-Myc-like functions of GpIbalpha. Instead, these require a more membrane-proximal filamin-binding domain. Also important is the GpIbalpha signal peptide, which, in the absence of other vWFR subunits, directs GpIbalpha to the endoplasmic reticulum rather than the membrane. Together, these results provide strong evidence that the domains of GpIbalpha mediating c-Myc-like functions are modular, genetically distinct, and independent of those involved in vWFR signaling.
Collapse
Affiliation(s)
- Youjun Li
- Section of Hematology/Oncology, Children's Hospital of Pittsburgh Pittsburgh, Pennsylvania 15213, USA
| | | | | |
Collapse
|
23
|
Juxtamembrane basic residues in glycoprotein Ibbeta cytoplasmic domain are required for assembly and surface expression of glycoprotein Ib-IX complex. FEBS Lett 2008; 582:3270-4. [PMID: 18789323 DOI: 10.1016/j.febslet.2008.08.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 08/03/2008] [Accepted: 08/06/2008] [Indexed: 11/21/2022]
Abstract
Platelet glycoprotein (GP) Ib-IX complex requires all its three subunits for efficient expression on the cell surface, but the underlying molecular basis is not fully clear. Using transfected Chinese hamster ovary cells as the model system, we demonstrate that juxtamembrane residues 149-154 in the cytoplasmic domain of the GPIbbeta subunit is required for assembly and surface expression of the GPIb-IX complex. The complex, or GPIbbeta by itself, lacking these residues is retained in the endoplasmic reticulum. Our results thus have illustrated an important role of the GPIbbeta cytoplasmic domain in biosynthesis of the GPIb-IX complex.
Collapse
|
24
|
Effect of Xiaoyu Zhixue Tablet on the expression of platelet membrane glycoprotein I b/IX/V complex in patients with chronic renal failure. Chin J Integr Med 2008; 14:83-7. [PMID: 18679596 DOI: 10.1007/s11655-008-0083-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Indexed: 10/21/2022]
Abstract
OBJECTIVE To investigate the effect of Xiaoyu Zhixue Tablet (XYZXT) on the expression of platelet membrane glycoprotein (GP) Ib/IX/V complex and GP I b alpha in patients with chronic renal failure (CRF) in early metaphase. METHODS Fifty-one patients with CRF in early metaphase (treated group) were treated with XYZXT, 3 months as the course of treatment for 2 courses. The previous therapies remained unchanged. Flow cytometry was used to assess the expression of platelet GP Ib/IX/V complex and GP Ib alpha in patients with CRF, and turbidity method was used to determine the platelet maximum aggregation rate (MAR), meanwhile the renal function was measured. The final data were compared with those before the treatment, and with those in the normal control group (31 healthy subjects). RESULTS Compared with the normal control group, expressions of GP I b/IX/V complex and GP I b alpha, and platelet MAR in CRF patients were significantly lower (P=0.007, P=0.001, P=0.009) before the treatment; after the treatment with XYZXT, the above indexes in CRF patients were remarkably increased (P=0.033, P=0.026, P=0.045), but still lower than those in the normal control group, however, it was not statistically significant. CONCLUSION (1) The expression of GP I b/IX/V complex in CRF patients of early metaphase was decreased, which lead to platelet aggregation dysfunction. This might be one of the reasons for the hemorrhagic trend in CRF. (2) XYZXT was able to upgrade expressions of GP I b/IX/V complex and GP I b alpha in CRF patients, improve platelet function and down-regulate platelet activation in patients with CRF.
Collapse
|
25
|
Luo SZ, Li R. Specific heteromeric association of four transmembrane peptides derived from platelet glycoprotein Ib-IX complex. J Mol Biol 2008; 382:448-57. [PMID: 18674540 DOI: 10.1016/j.jmb.2008.07.037] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2008] [Revised: 06/08/2008] [Accepted: 07/13/2008] [Indexed: 12/19/2022]
Abstract
As the receptor on the platelet surface for von Willebrand factor, glycoprotein (GP) Ib-IX complex is critically involved in hemostasis and thrombosis. How the complex is assembled from GP Ibalpha, GP Ib beta and GP IX subunits, all of which are type I transmembrane proteins, is not entirely clear. Genetic and mutational analyses have identified the transmembrane (TM) domains of these subunits as active participants in assembly of the complex. In this study, peptides containing the transmembrane domain of each subunit have been produced and their interaction with one another characterized. Only the Ib beta TM sequence, but not the Ibalpha and IX counterparts, can form homo-oligomers in SDS-PAGE and TOXCAT assays. Following up on our earlier observation that a Ib beta-Ibalpha-Ib beta peptide complex (alphabeta(2)) linked through native juxtamembrane disulfide bonds could be produced from isolated Ibalpha and Ib beta TM peptides in detergent micelles, we show here that addition of the IX TM peptide facilitates formation of the native alphabeta(2) complex, reproducing the same effect by the IX subunit in cells expressing the GP Ib-IX complex. Specific fluorescence resonance energy transfer was observed between donor-labeled alphabeta(2) peptide complex and acceptor-conjugated IX TM peptide in micelles. Finally, the mutation D135K in the IX TM peptide could hamper both the formation of the alphabeta(2) complex and the energy transfer, consistent with its reported effect in the full-length complex. Overall, our results have demonstrated directly the native-like heteromeric interaction among the isolated Ibalpha, Ib beta and IX TM peptides, which provides support for the four-helix bundle model of the TM domains in the GP Ib-IX complex and paves the way for further structural analysis. The methods developed in this study may be applicable to other studies of heteromeric interaction among multiple TM helices.
Collapse
Affiliation(s)
- Shi-Zhong Luo
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | | |
Collapse
|
26
|
Salles II, Feys HB, Iserbyt BF, De Meyer SF, Vanhoorelbeke K, Deckmyn H. Inherited traits affecting platelet function. Blood Rev 2008; 22:155-72. [DOI: 10.1016/j.blre.2007.11.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
27
|
Luo SZ, Mo X, López JA, Li R. Role of the transmembrane domain of glycoprotein IX in assembly of the glycoprotein Ib-IX complex. J Thromb Haemost 2007; 5:2494-502. [PMID: 17922811 PMCID: PMC2670928 DOI: 10.1111/j.1538-7836.2007.02785.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The glycoprotein (GP) Ib-IX complex is critically involved in platelet adhesion to von Willebrand factor and in the initial step of platelet activation. How this complex is assembled is not clear. We previously showed that the transmembrane (TM) domains of the GPIbalpha and GPIbbeta subunits interact and participate in complex assembly. OBJECTIVES AND METHODS Here, we have investigated the role of the TM and cytoplasmic domains of GPIX in assembly of the GPIb-IX complex, by analyzing the mutational effects on complex expression and assembly in transiently transfected Chinese hamster ovary cells. RESULTS Replacing the cytoplasmic domain of GPIX with a poly-alanine sequence had little effect on surface expression and structural integrity of the GPIb-IX complex. In contrast, replacing the GPIX TM domain (residues 132-153) with a poly-leucine-alanine sequence markedly disrupted complex formation of GPIX with GPIbalpha, interfered with GPIb formation, and decreased surface expression of the host complex. We further analyzed the contributions of a number of GPIX TM residues to complex formation by mutagenesis and found significant roles for Asp135 and several Leu residues. CONCLUSIONS The TM domain, rather than the cytoplasmic domain, of GPIX plays an important role in expression and assembly of the GPIb-IX complex by interacting with its counterparts of GPIb. These TM domains may form a parallel four-helical bundle structure in the complex.
Collapse
Affiliation(s)
- Shi-Zhong Luo
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Xi Mo
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - José A. López
- Puget Sound Blood Center, Division of Hematology, Department of Medicine, University of Washington, Seattle, Washington 98104
| | - Renhao Li
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030
| |
Collapse
|
28
|
Rosenberg N, Lalezari S, Landau M, Shenkman B, Seligsohn U, Izraeli S. Trp207Gly in platelet glycoprotein Ibalpha is a novel mutation that disrupts the connection between the leucine-rich repeat domain and the disulfide loop structure and causes Bernard-Soulier syndrome. J Thromb Haemost 2007; 5:378-86. [PMID: 17083647 DOI: 10.1111/j.1538-7836.2007.02298.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Bernard-Soulier syndrome (BSS) is a severe inherited bleeding disorder that is caused by a defect in glycoprotein (GP)Ib-IX-V complex, the platelet membrane receptor for von Willebrand factor. PATIENTS The diagnosis of BSS was made in two members of a Bukharian Jewish family who had life-long thrombocytopenia associated with mucocutaneous bleeding manifestations. METHODS AND RESULTS Flow cytometry and Western blot analyses showed only trace amounts of GPIb and GPIX on the patients' platelets. Sequence analysis of the GPIbalpha gene revealed a homozygous T > G transversion at nucleotide 709 predicting Trp207Gly substitution in the mature protein. Introduction of the mutation into a mammalian expression construct abolished the surface expression of GPIbalpha in transfected baby hamster kidney cells. The crystal structure of the N-terminus of GPIbalpha (PDB: 1SQ0) indicates that Trp207 is completely buried and located in a disulfide loop structure that interacts with the leucine-rich repeat (LRR) domain. CONCLUSION A novel mutation, Trp207Gly, causes BSS and predicts disruption of the interaction between a disulfide loop and the LRR domain that is essential for the integrity of GPIbalpha structure.
Collapse
Affiliation(s)
- N Rosenberg
- Amalia Biron Research Institute of Thrombosis and Hemostasis, Chaim Sheba Medical Center, Tel-Hashomer, Israel
| | | | | | | | | | | |
Collapse
|
29
|
Kunishima S, Sako M, Yamazaki T, Hamaguchi M, Saito H. Molecular genetic analysis of a variant Bernard?Soulier syndrome due to compound heterozygosity for two novel glycoprotein Ib? mutations. Eur J Haematol 2006; 77:501-12. [PMID: 16978236 DOI: 10.1111/j.0902-4441.2006.t01-1-ejh2817.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bernard-Soulier syndrome (BSS) is a rare bleeding disorder characterized by giant platelets, thrombocytopenia, and prolonged bleeding time. It is caused by abnormalities in the glycoprotein (GP) Ib/IX/V complex, the receptor for von Willebrand factor (vWF). Most cases of BSS described so far involve quantitative rather than qualitative defects in the complex. In this study, we investigated the effects of two naturally occurring mutations in the GPIbbeta gene, C122S and 443delG, on the expression of the GPIb/IX complex identified in a variant type of BSS in which the platelets had severely reduced GPIbalpha ( approximately 10%) and less markedly reduced GPIbbeta and GPIX ( approximately 20%) expression. Immunoblot analysis showed the absence of non-reduced GPIb (GPIbalpha/GPIbbeta) in the patient's platelets. Transient transfection experiments in 293T cells revealed the expression of GPIbbeta Ser122 polypeptide and absence of GPIbbeta 443delG polypeptide. Although no disulfide-linked association was observed between GPIbbeta Ser122 and GPIbalpha, GPIbbeta Ser122 was non-covalently associated with both GPIbalpha and GPIX subunits on the cell surface when cotransfected with wild-type GPIbalpha and GPIX. Chinese hamster ovary cells stably expressing GPIbalpha/Ibbeta Ser122/IX had the ability to bind soluble vWF and to aggregate in the presence of ristocetin. These results suggest that despite disruption of the disulfide linkage between GPIbalpha and GPIbbeta, GPIb/IX is formed, but its stability may be impaired, resulting in low levels of the complex on the platelet membranes.
Collapse
Affiliation(s)
- Shinji Kunishima
- Department of Hemostasis and Thrombosis, Clinical Research Center, National Hospital Organization Nagoya Medical Center, Nagoya, Japan.
| | | | | | | | | |
Collapse
|
30
|
Mo X, Lu N, Padilla A, López JA, Li R. The transmembrane domain of glycoprotein Ibbeta is critical to efficient expression of glycoprotein Ib-IX complex in the plasma membrane. J Biol Chem 2006; 281:23050-9. [PMID: 16757483 DOI: 10.1074/jbc.m600924200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lack of expression of glycoprotein (GP) Ib-IX-V complex in platelets often results from mutations in its three subunits: GP Ibalpha, GP Ibbeta, or GP IX. The requirement of all three subunits in the efficient surface expression of the receptor complex has been reproduced in Chinese hamster ovary cells. Here, we probed the role of the transmembrane domains in expression of the GP Ib-IX complex and potential interactions between these domains. Replacing the transmembrane domains of either GP Ibalpha or GP Ibbeta, but not that of GP IX, with unrelated sequences markedly diminished surface expression of the GP Ib-IX complex in transiently transfected Chinese hamster ovary cells. Replacement of the Ibbeta transmembrane domain produced the largest effect. Furthermore, several single-site mutations in the Ibbeta transmembrane domain were found to significantly decrease overall expression as well as surface expression of GP Ibalpha, probably by perturbing the interaction between the Ibalpha and Ibbeta transmembrane domains and in turn reducing the stability of GP Ibalpha in the cell. Mutations S503V and S503L in the Ibalpha transmembrane domain partly reversed the expression-decreasing effect of mutation H139L, but not the others, in the Ibbeta transmembrane domain, suggesting a specific interaction between these two polar residues. Together, our results have demonstrated the importance of the Ibbeta transmembrane domain, through its interaction with the Ibalpha counterpart, to the proper assembly and efficient surface expression of the GP Ib-IX complex.
Collapse
Affiliation(s)
- Xi Mo
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, Texas 77030, USA
| | | | | | | | | |
Collapse
|
31
|
Strassel C, David T, Eckly A, Baas MJ, Moog S, Ravanat C, Trzeciak MC, Vinciguerra C, Cazenave JP, Gachet C, Lanza F. Synthesis of GPIb beta with novel transmembrane and cytoplasmic sequences in a Bernard-Soulier patient resulting in GPIb-defective signaling in CHO cells. J Thromb Haemost 2006; 4:217-28. [PMID: 16409472 DOI: 10.1111/j.1538-7836.2005.01654.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The molecular defect of a new Bernard-Soulier patient, originating from Morocco and presenting thrombocytopenia with large platelets and an absence of ristocetin-induced platelet agglutination, has been identified and reproduced in transfected heterologous cells. Gene sequencing revealed insertion of a guanine in the domain coding for the transmembrane region of the glycoprotein (GP) Ib beta subunit. This mutation causes a translational frame shift, which creates putative novel transmembrane and cytoplasmic 37 and 125 amino acids domains, respectively. A 34 kDa immunoreactive GPIb beta band, instead of the normal 26 kDa subunit, was detected by Western blotting in lysates from the patient's platelets and from transfected cells and in immunoprecipitates of metabolically labeled cells. The abnormal subunit did not associate with GPIb alpha and was mainly intracellular, although a significant fraction could reach the cell surface. Cells expressing the mutant GPIb-IX complex adhered to a von Willebrand factor matrix but were unable to change shape, unlike cells expressing the wild-type receptor. These results strongly suggest a novel role of the GPIb beta subunit and its transmembrane-intracellular region in GPIb-VWF-dependent signaling, in addition to a role in correct assembly and cell surface targeting of the GPIb-V-IX complex.
Collapse
Affiliation(s)
- C Strassel
- INSERM U.311, Etablissement Français du Sang, Alsace, Strasbourg, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Feng S, Lu X, Kroll MH. Filamin A Binding Stabilizes Nascent Glycoprotein Ibα Trafficking and Thereby Enhances Its Surface Expression. J Biol Chem 2005; 280:6709-15. [PMID: 15623510 DOI: 10.1074/jbc.m413590200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The glycoprotein (Gp) Ib-IX-V complex is essential for platelet-mediated hemostasis and thrombosis. The cytoplasmic domain of its largest polypeptide subunit GpIbalpha possesses a binding region for filamin A, which links GpIb-IX-V to the platelet cytoskeleton. There is evidence that filamin A binding to GpIbalpha directs the surface expression of GpIb-IX. To investigate the mechanism of this effect, we examined GpIbalpha biosynthesis in Chinese hamster ovary (CHO) cells stably co-expressing wild-type or mutant GpIbalpha with GpIbbeta, GpIX with and without filamin A. We observed that surface GpIbalpha expression is enhanced in CHO cells co-expressing human filamin A. In comparison with cells expressing only GpIbalpha, GpIbbeta, and GpIX (CHO-GpIbalpha/betaIX), lysates from CHO-GpIbalpha/betaIX + filamin A-expressing cells showed greater amounts of immature, incompletely O-glycosylated and fully mature GpIbalpha, but lesser amounts of the approximately 15-kDa C-terminal peptide released when the extracellular domain of GpIbalpha is cleaved by proteases. When filamin A binding is eliminated by truncation of GpIbalpha at C-terminal residue 557 or by a deletion between amino acids 560-570, the decreased synthesis of mature GpIbalpha is accompanied by decreased immature GpIbalpha and by an increased immunodetectable C-terminal peptide. The synthesis of mature GpIbalpha in CHO-GpIbalpha/betaIX cells is eliminated by brefeldin A (which inhibits transport out of the endoplasmic reticulum (ER)) and restored by lactacystin (which inhibits proteasomal degradation). These results suggest that GpIbalpha binds to filamin A within the ER and that filamin A binding directs post-ER trafficking of GpIbalpha to the cell surface.
Collapse
Affiliation(s)
- Shuju Feng
- Michael E. DeBakey Veterans Affairs Medical Center, Baylor College of Medicine and Rice University, Houston, Texas 77030, USA
| | | | | |
Collapse
|
33
|
Drouin J, Carson NL, Laneuville O. Compound heterozygosity for a novel nine-nucleotide deletion and the Asn45Ser missense mutation in the glycoprotein IX gene in a patient with Bernard-Soulier syndrome. Am J Hematol 2005; 78:41-8. [PMID: 15609295 DOI: 10.1002/ajh.20236] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Bernard-Soulier syndrome (BSS) is a rare inherited bleeding disorder due to quantitative or qualitative abnormalities in the platelet glycoprotein (GP) Ib/IX/V complex, the major von Willebrand factor receptor. The complex comprises four subunits, each encoded by a separate gene. Several mutations have been described for each of the subunits, except for GPV, as a cause of BSS. We describe here the genetic basis of the disorder in a child with BSS. Flow-cytometric analysis of the patient's platelets showed a markedly reduced surface expression of all three glycoproteins of the GPIb/IX/V complex. DNA sequencing analysis showed the patient to be a compound heterozygote for two mutations in the GPIX gene, a novel nine-nucleotide deletion starting at position 1952 of the gene that changes asparagine 86 for alanine and eliminates amino acids 87, 88, and 89 (arginine, threonine, and proline) and a previously reported point mutation that changes the codon asparagine (AAC) for serine (AGC) at residue 45. Her mother was heterozygous for the Asn45Ser mutation, and her father, for the nine-nucleotide deletion. Our findings suggest that the additive effects of both mutations in the GPIX gene are responsible for the BSS phenotype of the patient.
Collapse
Affiliation(s)
- Jeanne Drouin
- Department of Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | | | | |
Collapse
|
34
|
Canobbio I, Balduini C, Torti M. Signalling through the platelet glycoprotein Ib-V–IX complex. Cell Signal 2004; 16:1329-44. [PMID: 15381249 DOI: 10.1016/j.cellsig.2004.05.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2004] [Accepted: 05/12/2004] [Indexed: 11/16/2022]
Abstract
The glycoprotein Ib-V-IX is one of the major adhesive receptors expressed on the surface of circulating platelets. It is composed of four different polypeptides-GPIbalpha, GPIbbeta, GPIX, and GPV-and represents a multifunctional receptor able to interact with a number of ligands, including the adhesive protein von Willebrand factor, the coagulation factors thrombin, factors XI and XII, and the membrane glycoproteins P-selectin and Mac-1. Interaction of GPIb-V-IX with the subendothelial von Willebrand factor is essential for primary haemostasis, as it initiates platelet adhesion to the subendothelial matrix at the sites of vascular injury even under high flow conditions. Upon interaction with von Willebrand factor, GPIb-V-IX initiates transmembrane signalling events for platelet activation, which eventually result in integrin alpha(IIb)beta(3) stimulation and platelet aggregation. The investigation of the biochemical mechanisms for platelet activation by GPIb-V-IX has attracted increasing attention during the last years. This review will describe and discuss recent findings that have provided new insights into the events underlying GPIb-V-IX transmembrane signalling. In particular, it will summarise basic concepts on the structure of this receptor, extracellular ligands, and intracellular interactors potentially involved in transmembrane signalling. The recently suggested role of membrane Fc receptors in GPIb-V-IX-initiated platelet activation will also be discussed, along with the involvement of lipid metabolising enzymes, tyrosine kinases, and the cytoskeleton in the crosstalk between GPIb-V-IX and integrin alpha(IIb)beta(3).
Collapse
Affiliation(s)
- Ilaria Canobbio
- Center of Excellence for Applied Biology, Department of Biochemistry, University of Pavia, via Bassi 21, Pavia 27100, Italy
| | | | | |
Collapse
|
35
|
Kanaji T, Russell S, Cunningham J, Izuhara K, Fox JEB, Ware J. Megakaryocyte proliferation and ploidy regulated by the cytoplasmic tail of glycoprotein Ibα. Blood 2004; 104:3161-8. [PMID: 15271795 DOI: 10.1182/blood-2004-03-0893] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
AbstractWe have investigated the ability of glycoprotein (GP) Ibα, a megakaryocytic gene product, to sequester the signal transduction protein 14-3-3ξ and to influence megakaryocytopoiesis. Using a Gp1ba–/– mouse colony, we compared the rescued phenotypes produced by a wild-type human GP Ibα allele or a similar allele containing a 6-residue cytoplasmic tail truncation that abrogates binding to 14-3-3ξ. The observed phenotypes illustrate an involvement for GP Ibα in thrombopoietin-mediated events of megakaryocyte proliferation, polyploidization, and the expression of apoptotic markers in maturing megakaryocytes. We developed a hypothesis for the involvement of a GP Ibα/14-3-3ξ/PI-3 kinase complex in regulating thrombopoietin-mediated responses. An observed increase in thrombopoietin-mediated Akt phosphorylation in the truncated variant supported the hypothesis and led to the development of a model in which the GP Ibα cytoplasmic tail sequestered signaling proteins during megakaryocytopoiesis and, as such, became a critical regulator in the temporal sequence of events that led to normal megakaryocyte maturation.
Collapse
Affiliation(s)
- Taisuke Kanaji
- Department of Molecular and Experimental Medicine, Division of Experimental Hemostasis and Thrombosis, Roon Research Center for Arteriosclerosis and Thrombosis, MEM175, 10550 N Torrey Pines Rd, La Jolla, CA 92037, USA
| | | | | | | | | | | |
Collapse
|
36
|
Strassel C, Moog S, Baas MJ, Cazenave JP, Lanza F. Biosynthesis of platelet glycoprotein V expressed as a single subunit or in association with GPIb-IX. ACTA ACUST UNITED AC 2004; 271:3671-7. [PMID: 15355344 DOI: 10.1111/j.1432-1033.2004.04304.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glycoprotein (GP) V is noncovalently linked to GPIbalpha, GPIbbeta and GPIX within the platelet GPIb-V-IX complex, a receptor for von Willebrand factor and thrombin. Two functions have been ascribed to GPV, namely, the modulation of thrombin- and collagen-dependent platelet responses. The biosynthesis of this molecule was investigated in pulse-chase metabolic labelling experiments performed in CHO cell lines transfected with GPV, alone or in the presence of GPIb-IX. GPV could not be detected at the surface of cells expressing the single subunit but was found instead as a soluble form in the culture medium. In pulse-chase studies, an immature 70 kDa protein was detected in cell lysates, whereas a fully processed 80-82 kDa form was only observed in the culture supernatants at later chase times. Immature GPV was N-glycosylated and retained before the medial Golgi while the secreted molecule contained complex sialylated sugars. The mature soluble form of GPV was produced by an enzymatic cleavage which was not affected by inhibitors of proteasome, calpain or metalloproteinases. When GPV was cotransfected with GPIb-IX, the former was no longer found in the culture supernatant but was retained in the cell membrane as shown by fluorescence-activated cell sorting and confocal microscopy analyses. Surface expressed GPV was processed from an immature 70 kDa form to produce a mature 80 kDa protein, processing similar to the intracellular trafficking of GPIbalpha. These results indicate that correct biosynthesis and surface expression of GPV in platelets requires the presence of the other subunits of the GPIb-V-IX complex.
Collapse
|
37
|
Martin K, Meade G, Moran N, Shields DC, Kenny D. A palmitylated peptide derived from the glycoprotein Ib beta cytoplasmic tail inhibits platelet activation. J Thromb Haemost 2003; 1:2643-52. [PMID: 14675101 DOI: 10.1046/j.1538-7836.2003.00478.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The platelet receptor GPIb/IX/V mediates a crucial role in hemostasis, yet the signaling mechanisms involved are incompletely understood. The complex consists of four polypeptides GPIb alpha, GPIb beta, GPIX and GPV. We identified an amino acid sequence in the cytoplasmic tail of the GPIb beta subunit between residues R151 and A161 that is highly conserved across species and hypothesized that it has functional importance. To target this motif, we synthesized a corresponding cell-permeable palmitylated peptide (Pal-RRLRARARARA) and investigated its effect on platelet function. Pal-RRLRARARARA completely inhibited low dose thrombin- and ristocetin-induced aggregation in washed platelets but only partially inhibited collagen- and U46619-induced aggregation. Thromboxane production in platelets stimulated with thrombin was significantly reduced by Pal-RRLRARARARA compared with collagen. Activation of the integrin alpha IIb beta 3 in response to thrombin was significantly reduced when platelets were preincubated with Pal-RRLRARARARA. The adhesion of washed platelets to von Willebrand factor (VWF) under static conditions was significantly reduced by Pal-RRLRARARARA. Under conditions of high shear, the velocity of platelets rolling on VWF was significantly increased when platelets are preincubated with Pal-RRLRARARARA. This study defines a novel function for the RRLRARARARA motif of GPIb beta in platelet activation.
Collapse
Affiliation(s)
- K Martin
- Department of Clinical Pharmacology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | | | | | | | | |
Collapse
|
38
|
Abstract
The biosynthesis of secretory and membrane proteins in the endoplasmic reticulum (ER) yields mostly properly folded and assembled structures with full biological activity. Such fidelity is maintained by quality control (QC) mechanisms that avoid the production of nonnative structures. QC relies on chaperone systems in the ER that monitor and assist in the folding process. When folding promotion is not sufficient, proteins are retained in the ER and eventually retranslocated to the cytosol for degradation by the ubiquitin proteasome pathway. Retention of proteins that fail QC can sometimes occur beyond the ER, and degradation can take place in lysosomes. Several diseases are associated with proteins that do not pass QC, fail to be degraded efficiently, and accumulate as aggregates. In other cases, pathology arises from the downregulation of mutated but potentially functional proteins that are retained and degraded by the QC system.
Collapse
Affiliation(s)
- E Sergio Trombetta
- Department of Cell Biology, Yale University School of Medicine, PO Box 208002, New Haven, Connecticut 06520-8002, USA.
| | | |
Collapse
|
39
|
Watanabe R, Ishibashi T, Saitoh Y, Shichishima T, Maruyama Y, Enomoto Y, Handa M, Oda A, Ambo H, Murata M, Ikeda Y. Bernard-soulier syndrome with a homozygous 13 base pair deletion in the signal peptide-coding region of the platelet glycoprotein Ib(beta) gene. Blood Coagul Fibrinolysis 2003; 14:387-94. [PMID: 12945881 DOI: 10.1097/00001721-200306000-00010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report a family with Bernard-Soulier syndrome with a homozygous mutation within the GPIb(beta) gene. The proband was a 24-year-old Japanese male who has suffered from life-long bleeding tendency. The patient's sister also had severe bleeding episodes. The proband and the affected sister had no apparent complications including organic or skeletal anomaly, or mental disturbance. They had thrombocytopenia [(35-40) x 10(9)/l] with giant platelets. In addition to platelet size, electron microscopic analysis revealed abnormalities in the internal structures of platelets. Ristocetin-induced platelet aggregation was defective. Flow cytometric analysis and western blot analysis showed that glycoprotein IX was nearly absent in platelets, whereas GPIb(alpha) and GPV were detectable. Genetic studies revealed a 13 base pair deletion in the signal peptide-coding sequence of GPIb(beta). The deletion would cause a frame-shift, resulting in the appearance of a stop codon following an indifferent polypeptide sequence. Analysis of platelet RNA showed that the mutant GPIb(beta) gene was transcribed. The propositus and his affected sister were homozygous for the deletion, whereas their unaffected father and mother were heterozygotes. The molecular defects of this family would help understand the relevance of GPIb(beta) for complex formation of the glycoprotein Ib/IX/V receptor.
Collapse
|
40
|
Tu L, Sun TT, Kreibich G. Specific heterodimer formation is a prerequisite for uroplakins to exit from the endoplasmic reticulum. Mol Biol Cell 2002; 13:4221-30. [PMID: 12475947 PMCID: PMC138628 DOI: 10.1091/mbc.e02-04-0211] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Much of the lower urinary tract, including the bladder, is lined by a stratified urothelium forming a highly differentiated, superficial umbrella cell layer. The apical plasma membrane as well as abundant cytoplasmic fusiform vesicles of the umbrella cells is covered by two-dimensional crystals that are formed by four membrane proteins named uroplakins (UPs) Ia, Ib, II, and III. UPs are synthesized on membrane-bound polysomes, and after several co- and posttranslational modifications they assemble into planar crystals in a post-Golgi vesicular compartment. Distension of the bladder may cause fusiform vesicles to fuse with the apical plasma membrane. We have investigated the early stages of uroplakin assembly by expressing the four uroplakins in 293T cells. Transfection experiments showed that, when expressed individually, only UPIb can exit from the endoplasmic reticulum (ER) and move to the plasma membrane, whereas UPII and UPIII reach the plasma membrane only when they form heterodimeric complexes with UPIa and UPIb, respectively. Heterodimer formation in the ER was confirmed by pulse-chase experiment followed by coimmunoprecipitation. Our results indicate that the initial building blocks for the assembly of crystalline uroplakin plaques are heterodimeric uroplakin complexes that form in the ER.
Collapse
Affiliation(s)
- Liyu Tu
- Department of Cell Biology, New York University, School of Medicine, New York, New York 10016, USA
| | | | | |
Collapse
|
41
|
Kenny D, Morateck PA, Montgomery RR. The cysteine knot of platelet glycoprotein Ib beta (GPIb beta) is critical for the interaction of GPIb beta with GPIX. Blood 2002; 99:4428-33. [PMID: 12036872 DOI: 10.1182/blood.v99.12.4428] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The glycoprotein Ib (GPIb) complex is composed of GPIb alpha covalently attached to GPIb beta and noncovalently complexed with GPIX and GPV. Patients with Bernard-Soulier syndrome demonstrate that mutations in either GPIb beta or GPIX result in an absence of platelet GPIb alpha. This occurs through the interaction of GPIX with GPIb beta. The precise sites of interaction of GPIb beta with GPIX are not known. To characterize the interaction of GPIb beta and GPIX, we developed an anti-GPIb beta monoclonal antibody MBC 257.4, whose epitope was in the N-terminal region of GPIb beta. N-terminal truncations of GPIb beta were expressed in mammalian cells. N-terminal truncations of GPIb beta, missing the first 14, 26, or 31 amino acids, were surface-expressed but did not enable coexpressed GPIX to be surface expressed, suggesting that the site of interaction with GPIX was modified by these deletions. GPIb beta and GPIX chimeras corresponding to predicted boundaries were used to define the sites of interaction of GPIb beta with GPIX. Replacing the N-terminal disulfide loops of GPIb beta (amino acids 1-14) with the corresponding disulfide loops of GPIX (amino acids 1-22) resulted in surface expression of coexpressed wildtype GPIX. However, when the N terminus of GPIb beta was replaced to residue 32 with the N terminus of GPIX (amino acids 1-36), GPIX did not surface express with this chimera. These results suggest that the cysteine knot region of GPIb beta in the N terminus is critical for the conformation of GPIb beta that interacts with GPIX and further suggests that a critical interaction of GPIb beta with GPIX involve residues 15 through 32 of GPIb beta
Collapse
Affiliation(s)
- Dermot Kenny
- Blood Research Institute, the Blood Center of Southeastern Wisconsin, Milwaukee, 53226-0509, USA.
| | | | | |
Collapse
|
42
|
Ulsemer P, Strassel C, Baas MJ, Salamero J, Chasserot-Golaz S, Cazenave JP, De La Salle C, Lanza F. Biosynthesis and intracellular post-translational processing of normal and mutant platelet glycoprotein GPIb-IX. Biochem J 2001; 358:295-303. [PMID: 11513727 PMCID: PMC1222061 DOI: 10.1042/0264-6021:3580295] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The multisubunit leucine-rich glycoprotein (GP) Ib-IX-V complex mediates von Willebrand factor-dependent platelet adhesion at sites of blood-vessel injury. Molecular defects of this receptor are reported to cause the Bernard-Soulier haemorrhagic disorder. To gain insight into the mechanisms controlling expression of normal and defective receptors, we performed pulse-chase metabolic studies and detailed analysis of intracellular processing in GPIb-IX-transfected Chinese-hamster ovary cells. In the native complex, after early subunit association, sugars N-linked to the three subunits are trimmed and sialylated in the Golgi compartment and GPIbalpha undergoes extensive O-glycosylation. Surface biotinylation during chase demonstrated that only fully processed complexes reach the cell surface. Tunicamycin treatment revealed that early N-glycosylation is not required for O-glycosylation of GPIbalpha and surface expression of the complex. Biosynthetic studies were then performed on a Bernard-Soulier variant based on previous description of abnormal GPIbalpha size and decreased surface expression. The mutant complex associated normally, but displayed defective processing of its N-linked sugars and abnormal O-glycosylation of GPIbalpha. Confocal immunofluorescence microscopy revealed that the mutant complexes could reach the cell surface but also accumulated intracellularly, while use of compartment specific markers showed strong co-localization in the endoplasmic reticulum (ER) and ER-to-Golgi intermediate compartments ('ERGIC') and only slight labelling of the cis-Golgi. Blockade before the Golgi was confirmed by brefeldin A treatment, which restored O-glycosylation and processing of N-linked sugars. The present study has shown that transfer from the ER to the Golgi represents an important step for controlling post-translational processing and surface expression of normal GPIb-IX-V complex.
Collapse
Affiliation(s)
- P Ulsemer
- INSERM U.311, Etablissement Français du Sang-Alsace, 10 rue Spielmann, BP 36, 67065 Strasbourg Cédex, France
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Antonucci JV, Martin ES, Hulick PJ, Joseph A, Martin SE. Bernard-Soulier syndrome: common ancestry in two African American families with the GP Ib alpha Leu129Pro mutation. Am J Hematol 2000; 65:141-8. [PMID: 10996832 DOI: 10.1002/1096-8652(200010)65:2<141::aid-ajh9>3.0.co;2-h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Bernard-Soulier syndrome (BSs) is a rare bleeding disorder characterized by circulating giant platelets, thrombocytopenia, and a prolonged bleeding time. BSs usually has an autosomal recessive inheritance pattern, with a preponderance of Caucasian and Japanese ancestry when the ethnic background has been reported. Underlying this disorder of platelet function is a defect in the platelet glycoprotein (GP) Ib-IX-V complex, composed of four polypeptides, GP Ib alpha, GP Ib beta, GP IX, and GP V. Molecular characterization of individuals with BSs has identified mutations in the GP Ib alpha, GP Ib beta, and GP IX genes responsible for the expressed phenotype. In this study, we report a family of African-American descent, with autosomal recessive BSs showing a point mutation in codon 129 of the GP Ib alpha gene. This mutation, CTC:wild-type to CCC:mutant, is similar to that of another African American family where the resulting leucine to proline substitution in the 5(th) leucine-rich repeat of GP Ib alpha is responsible for the observed BSs phenotype. Comparison of the intragenic polymorphisms of GP Ib alpha, as well as microsatellite markers in a 17.5 cM region of chromosome 17p12 that contains the GP Ib alpha gene, suggests that, although socially unrelated, the Leu129Pro mutation in these two families has a common founder.
Collapse
Affiliation(s)
- J V Antonucci
- Department of Medicine, Christiana Care Health System, Wilmington, Delaware, USA
| | | | | | | | | |
Collapse
|
44
|
Dong J, Schade AJ, Romo GM, Andrews RK, Gao S, McIntire LV, López JA. Novel gain-of-function mutations of platelet glycoprotein IBalpha by valine mutagenesis in the Cys209-Cys248 disulfide loop. Functional analysis under statis and dynamic conditions. J Biol Chem 2000; 275:27663-70. [PMID: 10837490 DOI: 10.1074/jbc.m909952199] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet-type von Willebrand disease is a bleeding disorder resulting from gain-of-function mutations of glycoprotein (GP) Ibalpha that increase its affinity for von Willebrand factor (vWf). The two known naturally occurring mutations, G233V and M239V, both enrich the valine content of an already valine-rich region within the Cys(209)-Cys(248) disulfide loop. We tested the effect of converting other non-valine residues in this region to valine. Of 10 mutants expressed in CHO cells as components of GP Ib-IX complexes, four displayed a gain-of-function phenotype (G233V, D235V, K237V, and M239V) based on (125)I-vWf binding and adhesion to immobilized vWf. The remainder displayed loss-of-function phenotypes. The gain-of-function mutants bound vWf spontaneously and had a heightened response to low concentrations of ristocetin or botrocetin, whereas the loss-of-function mutants bound vWf more poorly than wild-type GP Ibalpha. No distinct gain- or loss-of-function conformations were identified with conformation-sensitive antibodies. Compared with cells expressing wild-type GP Ibalpha, cells expressing the gain-of-function mutants rolled significantly more slowly over immobilized vWf under flow than wild-type cells and were able to adhere to vWf coated at lower densities. In aggregate, these data indicate that the region of GP Ibalpha bounded by Asn(226) and Ala(244) regulates the affinity for vWf.
Collapse
Affiliation(s)
- J Dong
- Thrombosis Research Section, Department of Internal Medicine and Department of Molecular and Human Genetics, Baylor College of Medicine and Veterans Affairs Medical Center, Houston, Texas 77030, USA
| | | | | | | | | | | | | |
Collapse
|
45
|
Surface expression of glycoprotein Ibα is dependent on glycoprotein Ibβ: evidence from a novel mutation causing Bernard-Soulier syndrome. Blood 2000. [DOI: 10.1182/blood.v96.2.532.014k33_532_539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bernard-Soulier syndrome is a rare bleeding disorder caused by a quantitative or qualitative defect in the platelet glycoprotein (GP) Ib-IX-V complex. The complex, which serves as a platelet receptor for von Willebrand factor, is composed of 4 subunits: GPIb, GPIbβ, GPIX, and GPV. We here describe the molecular basis of a novel form of Bernard-Soulier syndrome in a patient in whom the components of the GPIb-IX-V complex were undetectable on the platelet surface. Although confocal imaging confirmed that GPIb was not present on the platelet surface, GPIb was readily detectable in the patient's platelets. Moreover, immunoprecipitation of plasma with specific monoclonal antibodies identified circulating, soluble GPIb. DNA-sequence analysis revealed normal sequences for GPIb and GPIX. There was a G to A substitution at position 159 of the gene encoding GPIbβ, resulting in a premature termination of translation at amino acid 21. Studies of transient coexpression of this mutant, W21stop-GPIbβ, together with wild-type GPIb and GPIX, demonstrated a failure of GPIX expression on the surface of HEK 293T cells. Similar results were obtained with Chinese hamster ovary IX cells, a stable cell line expressing GPIb that retains the capacity to re-express GPIX. Thus, we found that GPIbβ affects the surface expression of the GPIb-IX complex by failing to support the insertion of GPIb and GPIX into the platelet membrane.
Collapse
|
46
|
Surface expression of glycoprotein Ibα is dependent on glycoprotein Ibβ: evidence from a novel mutation causing Bernard-Soulier syndrome. Blood 2000. [DOI: 10.1182/blood.v96.2.532] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractBernard-Soulier syndrome is a rare bleeding disorder caused by a quantitative or qualitative defect in the platelet glycoprotein (GP) Ib-IX-V complex. The complex, which serves as a platelet receptor for von Willebrand factor, is composed of 4 subunits: GPIb, GPIbβ, GPIX, and GPV. We here describe the molecular basis of a novel form of Bernard-Soulier syndrome in a patient in whom the components of the GPIb-IX-V complex were undetectable on the platelet surface. Although confocal imaging confirmed that GPIb was not present on the platelet surface, GPIb was readily detectable in the patient's platelets. Moreover, immunoprecipitation of plasma with specific monoclonal antibodies identified circulating, soluble GPIb. DNA-sequence analysis revealed normal sequences for GPIb and GPIX. There was a G to A substitution at position 159 of the gene encoding GPIbβ, resulting in a premature termination of translation at amino acid 21. Studies of transient coexpression of this mutant, W21stop-GPIbβ, together with wild-type GPIb and GPIX, demonstrated a failure of GPIX expression on the surface of HEK 293T cells. Similar results were obtained with Chinese hamster ovary IX cells, a stable cell line expressing GPIb that retains the capacity to re-express GPIX. Thus, we found that GPIbβ affects the surface expression of the GPIb-IX complex by failing to support the insertion of GPIb and GPIX into the platelet membrane.
Collapse
|
47
|
Rosado JA, Jenner S, Sage SO. A role for the actin cytoskeleton in the initiation and maintenance of store-mediated calcium entry in human platelets. Evidence for conformational coupling. J Biol Chem 2000; 275:7527-33. [PMID: 10713057 DOI: 10.1074/jbc.275.11.7527] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nature of the mechanism underlying store-mediated Ca(2+) entry has been investigated in human platelets through a combination of cytoskeletal modifications. Inhibition of actin polymerization by cytochalasin D or latrunculin A had a biphasic time-dependent effect on Ca(2+) entry, showing an initial potentiation followed by inhibition of Ca(2+) entry. Moreover, addition of these agents after induction of store-mediated Ca(2+) entry inhibited the Ca(2+) influx mechanism. Jasplakinolide, which reorganizes actin filaments into a tight cortical layer adjacent to the plasma membrane, prevented activation of store-mediated Ca(2+) entry but did not modify this process after its activation. In addition, jasplakinolide prevented cytochalasin D-induced inhibition of store-mediated Ca(2+) entry. Calyculin A, an inhibitor of protein serine/threonine phosphatases 1 and 2 which activates translocation of existing F-actin to the cell periphery without inducing actin polymerization, also prevented activation of store-mediated Ca(2+) entry. Finally, inhibition of vesicular transport with brefeldin A inhibited activation of store-mediated Ca(2+) entry but did not alter this mechanism once initiated. These data suggest that store-mediated Ca(2+) entry in platelets may be mediated by a reversible trafficking and coupling of the endoplasmic reticulum with the plasma membrane, which shows close parallels to the events mediating secretion.
Collapse
Affiliation(s)
- J A Rosado
- Department of Physiology, University of Cambridge, Downing Street, Cambridge CB2 3EG, United Kingdom
| | | | | |
Collapse
|
48
|
Kunishima S, Tomiyama Y, Honda S, Kurata Y, Kamiya T, Ozawa K, Saito H. Cys97-->Tyr mutation in the glycoprotein IX gene associated with Bernard-Soulier syndrome. Br J Haematol 1999; 107:539-45. [PMID: 10583255 DOI: 10.1046/j.1365-2141.1999.01733.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bernard-Soulier syndrome (BSS) is an autosomal recessive bleeding disorder due to quantitative or qualitative abnormalities in the glycoprotein (GP) Ib/IX/V complex, the platelet receptor for von Willebrand factor. We describe here the genetic basis of the disorder in a patient with BSS. Flow cytometric analysis of the patient's platelets showed a greatly reduced GPIbalpha and completely absent GPIX surface expression. Immunoblot analysis disclosed greatly reduced GPIbalpha and residual amounts of GPIbbeta and GPIX in the platelets. DNA sequencing analysis revealed the patient to be homozygous for a novel missense mutation in the GPIX gene that converts Cys (TGT) to Tyr (TAT) at residue 97. Transient transfection studies confirmed that mutant GPIX was not expressed on the transfected cells, showing that the mutation was responsible for the BSS phenotype observed in the patient.
Collapse
Affiliation(s)
- S Kunishima
- Japanese Red Cross Aichi Blood Centre, Seto, Aichi, Japan.
| | | | | | | | | | | | | |
Collapse
|