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Moieties of Complement iC3b Recognized by the I-domain of Integrin αXβ2
- Source :
- Molecules and Cells
- Publication Year :
- 2020
-
Abstract
- Complement fragment iC3b serves as a major opsonin for facilitating phagocytosis via its interaction with complement receptors CR3 and CR4, also known by their leukocyte integrin family names, αMβ2 and αXβ2, respectively. Although there is general agreement that iC3b binds to the αM and αX I-domains of the respective β2-integrins, much less is known regarding the regions of iC3b contributing to the αX I-domain binding. In this study, using recombinant αX I-domain, as well as recombinant fragments of iC3b as candidate binding partners, we have identified two distinct binding moieties of iC3b for the αX I-domain. They are the C3 convertase-generated N-terminal segment of the C3b α'- chain (α'NT) and the factor I cleavage-generated N-terminal segment in the CUBf region of α-chain. Additionally, we have found that the CUBf segment is a novel binding moiety of iC3b for the αM I-domain. The CUBf segment shows about a 2-fold higher binding activity than the α'NT for αX I-domain. We also have shown the involvement of crucial acidic residues on the iC3b side of the interface and basic residues on the I-domain side.
- Subjects :
- I-domain
Stereochemistry
αMβ2
Integrin
binding sites
protein-protein interactions
Integrin alphaXbeta2
Complement receptor
Complement factor I
Protein–protein interaction
law.invention
iC3b
03 medical and health sciences
αXβ2
0302 clinical medicine
law
parasitic diseases
Humans
complement
Amino Acid Sequence
Binding site
Molecular Biology
Opsonin
030304 developmental biology
0303 health sciences
biology
Chemistry
Cell Biology
General Medicine
Protein Structure, Tertiary
Complement C3b
biology.protein
Recombinant DNA
integrins
030217 neurology & neurosurgery
Protein Binding
Research Article
Subjects
Details
- ISSN :
- 02191032
- Volume :
- 43
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- Molecules and cells
- Accession number :
- edsair.doi.dedup.....6d53435e9bf4a61e47dcbbab9c5e6da9