Filamin A binding to the cytoplasmic tail of glycoprotein Ibα regulates von Willebrand factor–induced platelet activation
| Autor: | Shuju Feng, Michael H. Kroll, Xin Lu, Julio C. Reséndiz |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Cytoplasm
animal structures Filamins Molecular Sequence Data Immunology CHO Cells macromolecular substances Biology Filamin Platelet membrane glycoprotein Biochemistry Filamin binding chemistry.chemical_compound Contractile Proteins Cricetinae von Willebrand Factor Animals Humans Amino Acid Sequence Platelet activation Peptide sequence Cytoskeleton Microfilament Proteins Tyrosine phosphorylation Platelet Glycoprotein GPIb-IX Complex Cell Biology Hematology Platelet Activation Molecular biology Recombinant Proteins Protein Structure Tertiary Cell biology body regions Glycoprotein Ib chemistry Mutagenesis biology.protein Signal Transduction |
| Zdroj: | Blood. 102:2122-2129 |
| ISSN: | 1528-0020 0006-4971 |
| Popis: | We examined the hypothesis that filamin A binding to the cytoplasmic tail of platelet glycoprotein Ibα (GpIbα) is regulated by pathologic shear stress and modulates von Willebrand factor (VWF)–induced platelet activation. To begin, we examined filamin binding to GpIbα in Chinese hamster ovary cells coexpressing mutant human GpIb-IX and wild-type human filamin A. We observed that many different deletions and truncations N-terminal to GpIbα's cytoplasmic domain residue 594 disrupted filamin A binding, but that binding was unaffected by 14 different point mutations in hydrophilic residues between amino acids 557 and 593. To try to narrow GpIbα's filamin A–binding domain, we next measured the effect of several cytoplasmic domain peptides on human filamin A binding to a GST-GpIbα cytoplasmic domain fusion protein. One peptide (residues 557-575; designated “A4 peptide”) inhibited filamin A binding to the GST-GpIbα cytoplasmic domain fusion protein and competed with GpIbα for binding to filamin A. When the A4 peptide was delivered to intact human platelets using a carrier peptide, we observed the dose-dependent inhibition of VWF-induced platelet aggregation in response to both ristocetin and shear stress. The effect of the A4 peptide on shear-induced platelet aggregation was accompanied by the attenuation of shear-induced filamin A binding to GpIbα and diminished shear-dependent protein tyrosine phosphorylation. These results suggest that shear-dependent VWF-induced platelet activation affects filamin A binding to GpIb-IX-V, and that filamin A binding to the cytoplasmic tail of GpIbα regulates proaggregatory tyrosine kinase signaling. |
| Databáze: | OpenAIRE |
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