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The CD9, CD81, and CD151 EC2 domains bind to the classical RGD-binding site of integrin αvβ3
- Source :
- Biochemical Journal. 474:589-596
- Publication Year :
- 2017
- Publisher :
- Portland Press Ltd., 2017.
-
Abstract
- Tetraspanins play important roles in normal (e.g. cell adhesion, motility, activation, and proliferation) and pathological conditions (e.g. metastasis and viral infection). Tetraspanins interact with integrins and regulate integrin functions, but the specifics of tetraspanin–integrin interactions are unclear. Using co-immunoprecipitation with integrins as a sole method to detect interaction between integrins and full-length tetraspanins, it has been proposed that the variable region (helices D and E) of the extracellular-2 (EC2) domain of tetraspanins laterally associates with a non-ligand-binding site of integrins. We describe that, using adhesion assays, the EC2 domain of CD81, CD9, and CD151 bound to integrin αvβ3, and this binding was suppressed by cRGDfV, a specific inhibitor of αvβ3, and antibody 7E3, which is mapped to the ligand-binding site of β3. We also present evidence that the specificity loop of β3 directly bound to the EC2 domains. This suggests that the EC2 domains specifically bind to the classical ligand-binding site of αvβ3. αvβ3 was a more effective receptor for the EC2 domains than the previously known tetraspanin receptors α3β1, α4β1, and α6β1. Docking simulation predicted that the helices A and B of CD81 EC2 bind to the RGD-binding site of αvβ3. Substituting Lys residues at positions 116 and 144/148 of CD81 EC2 in the predicted integrin-binding interface reduced the binding of CD81 EC2 to αvβ3, consistent with the docking model. These findings suggest that, in contrast with previous models, the ligand-binding site of integrin αvβ3, a new tetraspanin receptor, binds to the constant region (helices A and B) of the EC2 domain.
- Subjects :
- Protein Conformation, alpha-Helical
0301 basic medicine
Integrin
Gene Expression
CHO Cells
Tetraspanin 24
Biochemistry
Tetraspanin 29
Tetraspanin 28
03 medical and health sciences
Cricetulus
0302 clinical medicine
Tetraspanin
Escherichia coli
Animals
Protein Interaction Domains and Motifs
Amino Acid Sequence
Cloning, Molecular
Binding site
Receptor
Cell adhesion
Molecular Biology
CD151
Binding Sites
Sequence Homology, Amino Acid
biology
Antibodies, Monoclonal
Cell Biology
Integrin alphaVbeta3
Recombinant Proteins
Cell biology
Molecular Docking Simulation
Kinetics
030104 developmental biology
Docking (molecular)
030220 oncology & carcinogenesis
embryonic structures
biology.protein
Protein Conformation, beta-Strand
Sequence Alignment
Protein Binding
CD81
Subjects
Details
- ISSN :
- 14708728 and 02646021
- Volume :
- 474
- Database :
- OpenAIRE
- Journal :
- Biochemical Journal
- Accession number :
- edsair.doi.dedup.....3194621a018dd2a496cea38aaeb079d0