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Developmental Immunology
Volume 9 (2002), Issue 3, Pages 127-134
http://dx.doi.org/10.1080/1044667031000137584

Phage Display Based Cloning of Proteins Interacting with the Cytoplasmic Tail of Membrane Immunoglobulins

1Department of Genetics and General Biology, Hellbrunnerstraβe 34, Salzburg A-5020, Austria
2DRFZ, Schumannstrasse 21/22, D-10117, Germany
3MPI for Immunobiology, Stübeweg 51, Freiburg D-79108, Germany
4SIAF, Obere Strasse 22, Davos CH-7270, Switzerland
5Department of Biochemistry I, Universitaetsstrasse 25, Bielefeld D-33615, Germany

Copyright © 2002 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The reduced quantity and quality of serum immunoglobulins (sIgs) in mutant mice expressing truncated cytoplasmic tails of IgE and IgG1 indicate an active role for the cytoplasmic domains of mIgG1 and mIgE. We used phage display technology to identify candidate proteins able to interact with the cytoplasmic tail of mIgE. Using a murine cDNA B cell library displayed on the surface of phage as prey and the 28 amino acid long cytoplasmic tail of IgE as bait, we isolated phage encoding the murine hematopoietic progenitor kinase 1 (HPK1). Surface plasmon resonance analysis measurements confirmed affinity of HPK1 to the mIgE cytoplasmic tail and revealed association to other immunoglobulin isotypes as well. Immunoprecipitation experiments, using lysates from two B cell lines expressing nitrophenyl (NP) specific mIgE molecules showed co-precipitation of IgE and HPK1. The interaction of HPK1 with the cytoplasmic domains of membrane immunoglobulins indicate an active role of the tails as part of an isotype specific signal transduction, independent from the Igα/Igβ heterodimers, and may represent a missing link to upstream regulatory elements of HPK1 activation.