Download MendeleyA Crystallin Fold in the Interleukin-4-Inducing Principle of Schistosoma Mansoni Eggs (Ipse/Alpha-1) Mediates Ige Binding for Antigen-Independent Basophil Activation
Meyer, N.H., Mayerhofer, H., Tripsianes, K., Barths, D., Blindow, S., Bade, S., Madl, T., Frey, A., Haas, H., Mueller-Dieckmann, J., Sattler, M., Scharmm, G.(2015) J Biological Chem 290: 22111
- PubMed: 26163514
- DOI: https://doi.org/10.1074/jbc.M115.675066
- Primary Citation of Related Structures:
4AKA, 4EL6 - PubMed Abstract:
The IL-4-inducing principle from Schistosoma mansoni eggs (IPSE/α-1), the major secretory product of eggs from the parasitic worm S. mansoni, efficiently triggers basophils to release the immunomodulatory key cytokine interleukin-4. Activation by IPSE/α-1 requires the presence of IgE on the basophils, but the detailed molecular mechanism underlying activation is unknown. NMR and crystallographic analysis of IPSEΔNLS, a monomeric IPSE/α-1 mutant, revealed that IPSE/α-1 is a new member of the βγ-crystallin superfamily. We demonstrate that this molecule is a general immunoglobulin-binding factor with highest affinity for IgE. NMR binding studies of IPSEΔNLS with the 180-kDa molecule IgE identified a large positively charged binding surface that includes a flexible loop, which is unique to the IPSE/α-1 crystallin fold. Mutational analysis of amino acids in the binding interface showed that residues contributing to IgE binding are important for IgE-dependent activation of basophils. As IPSE/α-1 is unable to cross-link IgE, we propose that this molecule, by taking advantage of its unique IgE-binding crystallin fold, activates basophils by a novel, cross-linking-independent mechanism.
- From the Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, the Munich Center for Integrated Protein Science and Biomolecular NMR, Department of Chemie, Technische Universität München, 85747 Garching.
Organizational Affiliation:
