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Shameer K, Denny JC, Ding K, Jouni H, Crosslin DR, de Andrade M, Chute CG, Peissig P, Pacheco JA, Li R, Bastarache L, Kho AN, Ritchie MD, Masys DR, Chisholm RL, Larson EB, McCarty CA, Roden DM, Jarvik GP, Kullo IJ. A genome- and phenome-wide association study to identify genetic variants influencing platelet count and volume and their pleiotropic effects. Hum Genet 2014; 133:95-109. [PMID: 24026423 PMCID: PMC3880605 DOI: 10.1007/s00439-013-1355-7] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 08/22/2013] [Indexed: 12/21/2022]
Abstract
Platelets are enucleated cell fragments derived from megakaryocytes that play key roles in hemostasis and in the pathogenesis of atherothrombosis and cancer. Platelet traits are highly heritable and identification of genetic variants associated with platelet traits and assessing their pleiotropic effects may help to understand the role of underlying biological pathways. We conducted an electronic medical record (EMR)-based study to identify common variants that influence inter-individual variation in the number of circulating platelets (PLT) and mean platelet volume (MPV), by performing a genome-wide association study (GWAS). We characterized genetic variants associated with MPV and PLT using functional, pathway and disease enrichment analyses; we assessed pleiotropic effects of such variants by performing a phenome-wide association study (PheWAS) with a wide range of EMR-derived phenotypes. A total of 13,582 participants in the electronic MEdical Records and GEnomic network had data for PLT and 6,291 participants had data for MPV. We identified five chromosomal regions associated with PLT and eight associated with MPV at genome-wide significance (P < 5E-8). In addition, we replicated 20 SNPs [out of 56 SNPs (α: 0.05/56 = 9E-4)] influencing PLT and 22 SNPs [out of 29 SNPs (α: 0.05/29 = 2E-3)] influencing MPV in a published meta-analysis of GWAS of PLT and MPV. While our GWAS did not find any new associations, our functional analyses revealed that genes in these regions influence thrombopoiesis and encode kinases, membrane proteins, proteins involved in cellular trafficking, transcription factors, proteasome complex subunits, proteins of signal transduction pathways, proteins involved in megakaryocyte development, and platelet production and hemostasis. PheWAS using a single-SNP Bonferroni correction for 1,368 diagnoses (0.05/1368 = 3.6E-5) revealed that several variants in these genes have pleiotropic associations with myocardial infarction, autoimmune, and hematologic disorders. We conclude that multiple genetic loci influence interindividual variation in platelet traits and also have significant pleiotropic effects; the related genes are in multiple functional pathways including those relevant to thrombopoiesis.
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Affiliation(s)
- Khader Shameer
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA
| | - Joshua C. Denny
- Departments of Medicine and Biomedical Informatics, Vanderbilt University, Nashville, TN 37232, USA
| | - Keyue Ding
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA
| | - Hayan Jouni
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA
| | - David R. Crosslin
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Mariza de Andrade
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Christopher G. Chute
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Peggy Peissig
- Biomedical Informatics Research Center, Marshfield Clinic, Marshfield, WI, 54449, USA
| | - Jennifer A. Pacheco
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Rongling Li
- Office of Population Genomics, National Human Genome Research Institute, 5635 Fishers Lane, Suite 3058, MSC 9307, Bethesda, MD, 20892, USA
| | - Lisa Bastarache
- Departments of Medicine and Biomedical Informatics, Vanderbilt University, Nashville, TN 37232, USA
| | - Abel N. Kho
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Marylyn D Ritchie
- Center for Systems Genomics, Pennsylvania State University, Eberly College of Science, The Huck Institutes of the Life Sciences, 512 Wartik Laboratory, University Park, PA 16802 USA
| | - Daniel R. Masys
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Room 416 Eskind Medical Library, Nashville, TN, 37232, USA
| | - Rex L. Chisholm
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Eric B. Larson
- Group Health Research Institute, 1730 Minor Avenue, Suite 1600, Seattle, WA, 98101, USA
| | | | - Dan M. Roden
- Department of Pharmacology, Vanderbilt University School of Medicine, 1285 Medical Research Building IV, Nashville, TN, 37232, USA
| | - Gail P. Jarvik
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle WA 98195, USA
| | - Iftikhar J. Kullo
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA
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Zurbano MJ, Fusté B, Arderiu G, Escolar G, Ordinas A, Díaz-Ricart M. Differences and similarities in tyrosine phosphorylation of proteins in platelets from human and pig species. J Thromb Haemost 2003; 1:2411-8. [PMID: 14629477 DOI: 10.1046/j.1538-7836.2003.00457.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: 11/20/2022]
Abstract
BACKGROUND Pigs have been widely used as animal models to study hemostasis. However, there are significant differences when comparing the hemostatic behavior of pig and human platelets. OBJECTIVE To investigate signaling through tyrosine-phosphorylation of proteins in pig platelets after activation in suspension or by adhesion under flow conditions, in comparison with human platelets. METHODS Activation of platelet suspensions was performed with thrombin (T; 0.1 and 1 U mL(-1)) and type I collagen (Col-I; 20 microg mL(-1)), at two different time points (30 and 90 s). Activation by adhesion was carried out on Col-I-coated coverslips, using citrated whole blood samples perfused through a parallel-plate chamber. RESULTS AND CONCLUSIONS Significant differences between pig and human platelets were detected before and after activation. Activation of pig platelets required higher concentrations of thrombin, as well as increased activation times, to achieve similar levels of tyrosine phosphorylation. Proteins p160, p140, p85 and pp62, present in human platelets, were not detected in profiles corresponding to activated pig platelets. A protein of 70 kDa appeared only in pig platelet profiles, p55 was highly phosphorylated, and the phosphorylation levels of some proteins were significantly different from those found in human platelet profiles. In profiles corresponding to adhered pig platelets, p85 and p62 were absent, and p115 appeared highly phosphorylated. As observed in suspension studies, p70 and p55 appeared specifically in adhered pig platelets. Our study shows that the phosphotyrosine proteins involved in the activation of pig platelets are significantly different from those observed in activated human platelets. These findings may help to explain the differing adhesive and cohesive properties of platelets from both species, which should be considered when extrapolating results.
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Affiliation(s)
- M J Zurbano
- Servicio Hemoterapia-Hemostasia, Hospital Clínic, IDIBAPS, Universidad de Barcelona, Spain
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Srivastava K, Dash D. Changes in membrane microenvironment and signal transduction in platelets from NIDDM patients-a pilot study. Clin Chim Acta 2002; 317:213-20. [PMID: 11814478 DOI: 10.1016/s0009-8981(01)00794-x] [Citation(s) in RCA: 11] [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
BACKGROUND Non-insulin-dependent diabetes mellitus (NIDDM) is characterized by the presence of abnormally active platelets in the circulation, leading to increased incidence of thrombotic complications. In this study, we have attempted to understand the pathophysiology of the platelets in NIDDM. METHODS Platelet aggregation was induced by thrombin receptor-activating peptide or epinephrine. Membrane fluidity was derived from the steady-state fluorescence anisotropy of diphenylhexatriene incorporated in the membrane. The phosphotyrosine content of the platelet proteins was probed using specific monoclonal antibodies. The extent of calpain activity was assessed from the proteolysis of calpain substrates. RESULTS Aggregation was significantly enhanced (p<0.001) in the platelets obtained from the cases of NIDDM. Anisotropy measurements reflected a significant increase in the microviscosity of platelet membranes from 3.315 (+/-0.103) in the control to 4.153 (+/-0.119) in NIDDM. Proteins of relative mobilities of 131, 100, 47 and 38 kDa were found to remain phosphorylated on tyrosine in the resting platelets obtained from NIDDM patients, while they were not phosphorylated in the control counterparts. This was associated with heightened activity of the calcium-dependent thiol protease, calpain, in NIDDM. CONCLUSIONS Taken together, these data indicated significant changes in the signaling mechanism in the platelets obtained from NIDDM, which could lead to platelet hyperactivity in this disease.
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Affiliation(s)
- Kalyan Srivastava
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, 221005, Varanasi, India
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Srivastava K, Dash D. Altered membrane fluidity and signal transduction in the platelets from patients of thrombotic stroke. Mol Cell Biochem 2001; 224:143-9. [PMID: 11693191 DOI: 10.1023/a:1011979801366] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Several earlier studies have implicated platelet activation with the pathogenesis of thrombotic stroke. In this report we have studied the changes in membrane physical microenvironment and signal transduction in the platelets obtained from the patients with thrombotic stroke. Aggregation induced by the synthetic agonist thrombin receptor-activating peptide was significantly enhanced (p < 0.001) in the platelets obtained from the patients. Steady-state fluorescence anisotropy measurements using diphenylhexatriene reflected a significant increase in membrane microviscosity from 3.315 (+/- 0.103) in the control to 4.600 (+/- 0.119) in the stroke. Proteins of relative mobilities of 131, 100, 47 and 38 kDa were found to remain phosphorylated on tyrosine in the resting platelets obtained from thrombotic stroke patients while they were not phosphorylated in the control counter-parts. Besides, calpain, a calcium dependent thiol protease present in the platelets, was found to remain active in this disease as reflected from the proteolysis of calpain substrates. Taken together, these data indicated abnormal circulating platelets in the patients ofthrombotic stroke. which could contribute to the etiopathogenesis of this disease.
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Affiliation(s)
- K Srivastava
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Inidia
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McNicol A, Shibou TS, Pampolina C, Israels SJ. Incorporation of map kinases into the platelet cytoskeleton. Thromb Res 2001; 103:25-34. [PMID: 11434943 DOI: 10.1016/s0049-3848(01)00271-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Erk1 (p44) and erk2 (p42) mitogen-activated protein (MAP) kinases are activated in agonist-stimulated platelets, although their role(s) in the activation process is unknown. In the present study, erk1, erk2 and the phosphorylated forms of both enzymes became associated with the contractile cytoskeleton in thrombin-stimulated platelets. Enzyme incorporation was accompanied by an increase in MAP kinase activity in the cytoskeleton, which was inhibited by PD98059. Pretreatment of the platelets with the arginine-glycine-aspartic acid-serine (RGDS) polypeptide enhanced both the cytoskeletal association and the enzyme activity, but cytochalasin D had no significant effect. Platelets from a patient with Glanzmann's thrombasthenia lack the alpha(IIb)beta(3) integrin and form only a rudimentary cytoskeleton, however, this cytoskeleton is enriched with both erk1 and erk2. These data suggest either that MAP kinases play a role in cytoskeletal rearrangement or that the cytoskeleton act as a frame to align MAP kinases with substrates in a highly integrated signal transduction pathway.
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Affiliation(s)
- A McNicol
- Department of Oral Biology, University of Manitoba, R3E 0W2, Winnipeg, Manitoba, Canada.
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Klages B, Brandt U, Simon MI, Schultz G, Offermanns S. Activation of G12/G13 results in shape change and Rho/Rho-kinase-mediated myosin light chain phosphorylation in mouse platelets. J Cell Biol 1999; 144:745-54. [PMID: 10037795 PMCID: PMC2132941 DOI: 10.1083/jcb.144.4.745] [Citation(s) in RCA: 271] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/1998] [Revised: 01/19/1999] [Indexed: 11/22/2022] Open
Abstract
Platelets respond to various stimuli with rapid changes in shape followed by aggregation and secretion of their granule contents. Platelets lacking the alpha-subunit of the heterotrimeric G protein Gq do not aggregate and degranulate but still undergo shape change after activation through thromboxane-A2 (TXA2) or thrombin receptors. In contrast to thrombin, the TXA2 mimetic U46619 led to the selective activation of G12 and G13 in Galphaq-deficient platelets indicating that these G proteins mediate TXA2 receptor-induced shape change. TXA2 receptor-mediated activation of G12/G13 resulted in tyrosine phosphorylation of pp72(syk) and stimulation of pp60(c-src) as well as in phosphorylation of myosin light chain (MLC) in Galphaq-deficient platelets. Both MLC phosphorylation and shape change induced through G12/G13 in the absence of Galphaq were inhibited by the C3 exoenzyme from Clostridium botulinum, by the Rho-kinase inhibitor Y-27632 and by cAMP-analogue Sp-5,6-DCl-cBIMPS. These data indicate that G12/G13 couple receptors to tyrosine kinases as well as to the Rho/Rho-kinase-mediated regulation of MLC phosphorylation. We provide evidence that G12/G13-mediated Rho/Rho-kinase-dependent regulation of MLC phosphorylation participates in receptor-induced platelet shape change.
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Affiliation(s)
- B Klages
- Institut für Pharmakologie, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, 14195 Berlin, Germany
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Kato A. The biologic and clinical spectrum of Glanzmann's thrombasthenia: implications of integrin alpha IIb beta 3 for its pathogenesis. Crit Rev Oncol Hematol 1997; 26:1-23. [PMID: 9246538 DOI: 10.1016/s1040-8428(97)00011-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- A Kato
- Department of Medicine, Juntendo University, Tokyo, Japan
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Abstract
AbstractNNKY5-5, an IgG monoclonal antibody directed against the von Willebrand factor-binding domain of glycoprotein (GP) Ibα, induced weak but irreversible aggregation (or association) of platelets in citrate-anticoagulated platelet-rich plasma. This phenomenon was defined as small aggregate formation (SAF ). Platelets in hirudin-anticoagulated plasma or washed platelets showed little response to NNKY5-5 alone, but the antibody potentiated aggregation induced by low concentrations of adenosine diphosphate or platelet-activating factor. NNKY5-5 did not induce granule release or intracellular Ca2+ mobilization. However, NNKY5-5 caused tyrosine phosphorylation of a 64-kD protein and activation of a tyrosine kinase, p72syk. An anti-FcγII receptor antibody had no effect on SAF, suggesting that NNKY5-5 activated platelets by interacting with glycoprotein Ib. Fab′ fragments of NNKY5-5 did not induce SAF, but potentiated aggregation induced by other agonists. The Fab′ fragment of NNKY5-5 induced the activation of p72syk, suggesting that such activation was independent of the FcγII receptor. Cross-linking of the receptor-bound Fab′ fragment of NNKY5-5 with a secondary antibody induced SAF. GRGDS peptide, chelation of extracellular Ca2+, and an anti-GPIIb/IIIa antibody inhibited NNKY5-5-induced SAF, but had no effect on 64-kD protein tyrosine phosphorylation or p72syk activations. Various inhibitors, including aspirin and protein kinase C, had no effect on SAF, protein tyrosine phosphorylation, or p72syk activation. In contrast, tyrphostin 47, a potent tyrosine kinase inhibitor, inhibited NNKY5-5–induced SAF as well as tyrosine phosphorylation and p72syk activation. Our findings suggest that binding of NNKY5-5 to GPIb potentiates platelet aggregation by facilitating the interaction between fibrinogen and GPIIb/IIIa through a mechanism associated with p72syk activation and tyrosine phosphorylation of a 64-kD protein.
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Abstract
NNKY5-5, an IgG monoclonal antibody directed against the von Willebrand factor-binding domain of glycoprotein (GP) Ibα, induced weak but irreversible aggregation (or association) of platelets in citrate-anticoagulated platelet-rich plasma. This phenomenon was defined as small aggregate formation (SAF ). Platelets in hirudin-anticoagulated plasma or washed platelets showed little response to NNKY5-5 alone, but the antibody potentiated aggregation induced by low concentrations of adenosine diphosphate or platelet-activating factor. NNKY5-5 did not induce granule release or intracellular Ca2+ mobilization. However, NNKY5-5 caused tyrosine phosphorylation of a 64-kD protein and activation of a tyrosine kinase, p72syk. An anti-FcγII receptor antibody had no effect on SAF, suggesting that NNKY5-5 activated platelets by interacting with glycoprotein Ib. Fab′ fragments of NNKY5-5 did not induce SAF, but potentiated aggregation induced by other agonists. The Fab′ fragment of NNKY5-5 induced the activation of p72syk, suggesting that such activation was independent of the FcγII receptor. Cross-linking of the receptor-bound Fab′ fragment of NNKY5-5 with a secondary antibody induced SAF. GRGDS peptide, chelation of extracellular Ca2+, and an anti-GPIIb/IIIa antibody inhibited NNKY5-5-induced SAF, but had no effect on 64-kD protein tyrosine phosphorylation or p72syk activations. Various inhibitors, including aspirin and protein kinase C, had no effect on SAF, protein tyrosine phosphorylation, or p72syk activation. In contrast, tyrphostin 47, a potent tyrosine kinase inhibitor, inhibited NNKY5-5–induced SAF as well as tyrosine phosphorylation and p72syk activation. Our findings suggest that binding of NNKY5-5 to GPIb potentiates platelet aggregation by facilitating the interaction between fibrinogen and GPIIb/IIIa through a mechanism associated with p72syk activation and tyrosine phosphorylation of a 64-kD protein.
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Abstract
This review article describes the different receptors, second-messengers and mechanisms involved in platelet activation. Several platelet agonists have well-defined receptors at the platelet membrane of which a number are single polypeptides with 7 hydrophobic transmembrane domains. These receptors are connected, via GTP regulatory proteins, with cytoplasmic second-messenger-generating enzymes. Phospholipase C and adenylate cyclase are the two best-known enzymes, generating inositol triphosphate (IP3) and diacyl glycerol from phosphatidylinositol biphosphate and cyclic AMP from ATP respectively. The intraplatelet free calcium level, which is critical for the activation status of the platelet, is increased by IP3 and is lowered in the presence of rising cyclic AMP concentrations. Shape-change occurs with small increases in intraplatelet calcium, while aggregation and secretion of granules take place at higher calcium, levels. The role of myosin and actin filaments and of transmembrane glycoproteins is further discussed.
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Affiliation(s)
- D Blockmans
- Department of Internal Medicine, Katholieke Universiteit Leuven, Belgium
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Nakamura K, Kimura M, Aviv A. Role of cyclic nucleotides in store-mediated external Ca2+ entry in human platelets. Biochem J 1995; 310 ( Pt 1):263-9. [PMID: 7544116 PMCID: PMC1135882 DOI: 10.1042/bj3100263] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This study explores the role of cyclic nucleotides (i.e. cyclic AMP and cyclic GMP) in store-regulated external Ca2+ entry in human platelets. To stimulate store-regulated external Ca2+ entry, thapsigargin was used to deplete Ca2+ from the dense tubules, and sodium nitroprusside and iloprost respectively were used to stimulate endogenous cyclic GMP and cyclic AMP formation. Pretreatment with sodium nitroprusside and iloprost (a) attenuated the thapsigargin-evoked external Ca2+ entry and (b) reduced the rate of Ca2+ release from the dense tubules. The effects on external Ca2+ entry and Ca2+ release from the dense tubules were exerted independently and were apparently mediated through activation of the respective cyclic nucleotide-dependent protein kinases. Both sodium nitroprusside and iloprost reduced tyrosine kinase phosphorylation of a number of proteins, particularly a 72 kDa protein band. Both agents also attenuated the thapsigargin-evoked tyrosine kinase phosphorylation of the 72 kDa band. Intracellular Ca2+ depletion resulted in a reduction in tyrosine kinase-mediated phosphorylation of a number of protein bands, including the 72 kDa band and the further attenuation of thapsigargin-mediated tyrosine phosphorylation of this band. The effects of the cyclic nucleotides on cellular Ca2+ homoeostasis in thapsigargin-treated platelets were not exerted via acceleration of Ca2+ extrusion or Ca2+ sequestration into the mitochondria. We conclude that cyclic nucleotides participate in store-regulated control of external Ca2+ entry by slowing down the rate of external Ca2+ entry and Ca2+ release from intracellular Ca2+ stores. These effects are apparently mediated via cyclic nucleotide-dependent protein kinases and the attenuation of protein phosphorylation by tyrosine kinases.
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Affiliation(s)
- K Nakamura
- Hypertension Research Center, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark 07103-2714, USA
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Roberts JJ, Rodgers SE, Drury J, Ashman LK, Lloyd JV. Platelet activation induced by a murine monoclonal antibody directed against a novel tetra-span antigen. Br J Haematol 1995; 89:853-60. [PMID: 7772522 DOI: 10.1111/j.1365-2141.1995.tb08424.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
MAb 14A2.H1 identifies a novel low-abundance platelet surface antigen, PETA-3, which is a member of the tetra-span (TM4) family. This MAb brings about platelet aggregation and mediator release, which is completely inhibitable by prostaglandin E1, and partially inhibitable by aspirin and ketanserin. Platelet activation by MAb 14A2.H1 is dependent on interaction with both the platelet Fc receptor, Fc gamma RII, and the specific antigen as it was prevented by either a blocking MAb to Fc gamma RII (IV.3) or F(ab')2 fragments of 14A2.H1. The extent of platelet activation by the antibody varied considerably between donors, and is believed to reflect the polymorphism of Fc gamma RII. Subaggregating concentrations of 14A2.H1 synergized with other platelet agonists, ADP, adrenaline, collagen and serotonin, indicating signalling via a pathway distinct from these activators. Synergy was also blocked by MAb IV.3, or F(ab')2 fragments of 14A2.H1. The similar low copy number of PETA-3 and Fc gamma RII in the platelet membrane (approximately 1000/platelet), together with the dependence on Fc gamma RII for activation by MAb 14A2.H1, suggests that PETA-3 may be a component of the Fc gamma RII signal transducing complex in platelets.
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Affiliation(s)
- J J Roberts
- Department of Clinical and Experimental Pharmacology, University of Adelaide, South Australia
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Avraham S, Jiang S, Ota S, Fu Y, Deng B, Dowler LL, White RA, Avraham H. Structural and functional studies of the intracellular tyrosine kinase MATK gene and its translated product. J Biol Chem 1995; 270:1833-42. [PMID: 7530249 DOI: 10.1074/jbc.270.4.1833] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We recently cloned the cDNA which encodes a novel megakaryocyte-associated tyrosine kinase termed MATK. In this study, we have cloned and characterized the human MATK gene as well as the murine homolog of human MATK cDNA and performed functional studies of its translated product. Comparison of the deduced amino acid sequences of human and murine MATK cDNAs revealed 85% homology, indicating that MATK is highly conserved in mouse and human. The human gene consists of 13 exons interrupted by 12 introns. The genetic units which encode the SH3 and SH2 domains are located on separate exons. The putative ATP binding site (GXGXXG) is localized on exon 7, and the entire catalytic domain is subdivided into seven exons (7-13). Somatic cell hybrid analysis indicated that human MATK gene is located on chromosome 19 while the murine Matk gene is located on chromosome 10. The immediate 5'-flanking region was highly rich in GC sequences, and potential cis-acting elements were identified including several SP1, GATA-1, APRE, and APRE1. Antisense oligonucleotides directed against MATK mRNA sequences significantly inhibited megakaryocyte progenitor proliferation. Functional studies indicated that MATK can phosphorylate the carboxyl-terminal conserved tyrosine of the Src protein. These results support the notion that MATK acts as a regulator of p60c-src in megakaryocytic cells and participates in the pathways regulating growth of cells of this lineage.
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Affiliation(s)
- S Avraham
- Division of Hematology/Oncology, New England Deaconess Hospital, Harvard Medical School, Boston, Massachusetts 02215
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Chacko GW, Duchemin AM, Coggeshall KM, Osborne JM, Brandt JT, Anderson CL. Clustering of the platelet Fc gamma receptor induces noncovalent association with the tyrosine kinase p72syk. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)31653-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Tyrosine kinases regulate the cytoskeletal attachment of integrin alpha IIb beta 3 (platelet glycoprotein IIb/IIIa) and the cellular retraction of fibrin polymers. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)31660-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Dhar A, Shukla S. Electrotransjection of pp60v-src monoclonal antibody inhibits activation of phospholipase C in platelets. A new mechanism for platelet-activating factor responses. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37085-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Kramer RM, Roberts EF, Manetta JV, Hyslop PA, Jakubowski JA. Thrombin-induced phosphorylation and activation of Ca(2+)-sensitive cytosolic phospholipase A2 in human platelets. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74383-x] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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