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Mitigation of Blood Borne Cell Attachment to Metal Implants through CD47-Derived Peptide Immobilization
Published on: December 3, 2020
Novel structural determinants on SIRP alpha that mediate binding to CD47.
Winston Y Lee1, Dominique A Weber, Oskar Laur
1Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|November 21, 2007
Summary
Signal regulatory proteins (SIRPs) bind CD47, crucial for innate immunity. Researchers identified specific residues on SIRP-alpha critical for CD47 binding, revealing a novel binding site that could inform new inflammation therapies.
Area of Science:
- Immunology
- Structural Biology
- Protein-Ligand Interactions
Background:
- Signal regulatory proteins (SIRPs) are key regulators of innate immune functions, including leukocyte migration.
- SIRP-alpha, -beta, and -gamma proteins share homologous extracellular domains, with D1 domains mediating CD47 binding for SIRP-alpha and SIRP-gamma.
Purpose of the Study:
- To investigate the specific residues within SIRP-alpha's D1 domain responsible for CD47 binding.
- To elucidate the structural basis of SIRP-alpha and CD47 interactions for potential therapeutic insights.
Main Methods:
- Site-directed mutagenesis to alter SIRP-alpha residues and assess CD47 binding.
- Residue exchange between SIRP-alpha and SIRP-beta to identify critical binding determinants.
- Homology modeling and analysis of the SIRP-alpha D1 domain structure.
- Epitope mapping of anti-SIRP antibodies.
Main Results:
- SIRP-alpha binding to CD47 is independent of N-glycosylation.
- Three critical residues in SIRP-alpha were identified for CD47 binding.
- Mutating SIRP-beta with these residues conferred de novo CD47 binding.
- A novel CD47 binding region on SIRP-alpha was identified, distinct from a previously described site.
Conclusions:
- SIRP-alpha's interaction with CD47 is complex, involving at least two distinct adjacent regions on the D1 domain.
- Understanding these structural requirements offers potential for developing therapeutics targeting inflammatory diseases.
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