Download MendeleyAffimer proteins inhibit immune complex binding to Fc gamma RIIIa with high specificity through competitive and allosteric modes of action.
Robinson, J.I., Baxter, E.W., Owen, R.L., Thomsen, M., Tomlinson, D.C., Waterhouse, M.P., Win, S.J., Nettleship, J.E., Tiede, C., Foster, R.J., Owens, R.J., Fishwick, C.W.G., Harris, S.A., Goldman, A., McPherson, M.J., Morgan, A.W.(2018) Proc Natl Acad Sci U S A 115: E72-E81
- PubMed: 29247053
- DOI: https://doi.org/10.1073/pnas.1707856115
- PubMed Abstract:
Protein-protein interactions are essential for the control of cellular functions and are critical for regulation of the immune system. One example is the binding of Fc regions of IgG to the Fc gamma receptors (FcγRs). High sequence identity (98%) between the genes encoding FcγRIIIa (expressed on macrophages and natural killer cells) and FcγRIIIb (expressed on neutrophils) has prevented the development of monospecific agents against these therapeutic targets. We now report the identification of FcγRIIIa-specific artificial binding proteins called "Affimer" that block IgG binding and abrogate FcγRIIIa-mediated downstream effector functions in macrophages, namely TNF release and phagocytosis. Cocrystal structures and molecular dynamics simulations have revealed the structural basis of this specificity for two Affimer proteins: One binds directly to the Fc binding site, whereas the other acts allosterically.
Organizational Affiliation:
Leeds Institute of Rheumatic and Musculoskeletal Medicine, School of Medicine, University of Leeds, Leeds LS9 7TF, United Kingdom.
