Something to sneeze about
For many people, spring brings the beauty of life dormant during a harsh winter; for some others, it signals the beginning of another allergy season. Allergy is caused by our body's response mounted against harmless foreign substances called allergens, such as pollen or food. The response is often immediate after exposure to the allergen, and the severity of the symptom ranges from a rash or constant sneezing to difficulty breathing that could sometimes be life-threatening.
The allergy response is mediated by an antibody called immunoglobulin E (IgE) bound to its receptor on the cell surface. The immediacy of the response is due to the high affinity between the two molecules - and therefore the long lifetime of the complex - thus priming the cell to quickly react to an allergen. However, the receptor binding regions of all antibodies are highly conserved, suggesting similar interaction surfaces. What, then, contributes to the high affinity between IgE and its receptor?
To address this question, David Cowburn and colleagues at the Rockefeller University, USA, and collaborators at King's College, UK, have characterized the receptor binding region of IgE (Nature Structural Biology, Vol. 8, No. 5, 01 May 2001). They showed that deletion of a domain called Ce2 in IgE significantly shortens the lifetime of the IgE-receptor complex. Using a variety of biophysical experiments, they found that Ce2 interacts with the IgE receptor and with a neighboring domain, Ce3, of IgE. The authors also determined the structure of the Ce2 domain and mapped its interaction surface with the IgE receptor by NMR spectroscopy. Because Ce2 contributes to the long lifetime of the IgE-receptor complex and thus the immediate allergy response, the interaction interface identified in this study provides a potential target for developing treatments against allergy diseases.
Dr. David Cowburn
The Rockefeller University
Dept. of Physical Biochemistry
1230 York Avenue
New York, NY 10021-6399
Dr. Hannah J. Gould
The Randall Centre for Molecular Mechanisms of Cell Function
New Hunt's House
London, SE1 3QU
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(C) Nature Structural Biology press release.
Message posted by: Trevor M. D'Souza