Abstract
A peptide from the C-terminal domain of thrombospondin-1 (4N1-1) has been proposed to stimulate platelet aggregation by a novel mechanism involving both an activation-independent agglutination and an activation-dependent, glycoprotein (GP) IIb/IIIa-mediated aggregation which involves GPVI signaling but does not involve CD47. The present study demonstrates that 4N1-1 stimulated a different pattern of signal transduction pathways than the GPVI agonist convulxin. Furthermore, 4N1-1-induced platelet aggregation was activation-independent and not dependent on GPVI or GPIIb/IIIa. Interestingly, 4N1-1 also stimulated activation-independent agglutination of different megakaryocytic and non-megakaryocytic cells. 4N1-1-induced cell agglutination but not platelet signaling was inhibited by anti-CD47 antibodies.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antigens, CD / biosynthesis
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Antigens, CD / metabolism
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Arteries / cytology
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Blood Platelets / metabolism*
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Blotting, Western
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CD47 Antigen
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Calcium / metabolism
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Carrier Proteins / biosynthesis
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Carrier Proteins / metabolism
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Cells, Cultured
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Dose-Response Relationship, Drug
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Flow Cytometry
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Humans
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Integrin beta3 / metabolism
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Megakaryocytes / metabolism
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Mitogen-Activated Protein Kinases / metabolism
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P-Selectin / biosynthesis
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Peptides
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Platelet Membrane Glycoprotein IIb / metabolism
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Protein Binding
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Protein Structure, Tertiary
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Signal Transduction
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Thrombospondin 1 / chemistry*
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Tumor Cells, Cultured
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U937 Cells
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p38 Mitogen-Activated Protein Kinases
Substances
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Antigens, CD
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CD47 Antigen
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CD47 protein, human
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Carrier Proteins
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Integrin beta3
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P-Selectin
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Peptides
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Platelet Membrane Glycoprotein IIb
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Thrombospondin 1
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Mitogen-Activated Protein Kinases
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p38 Mitogen-Activated Protein Kinases
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Calcium