1. The junction-associated protein AF-6 interacts and clusters with specific Eph receptor tyrosine kinases at specialized sites of cell-cell contact in the brain.
- Author
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Buchert M, Schneider S, Meskenaite V, Adams MT, Canaani E, Baechi T, Moelling K, and Hovens CM
- Subjects
- Animals, Binding Sites, Cell Line, Cell Line, Transformed, Cell Membrane metabolism, Dogs, Hippocampus metabolism, Humans, Intercellular Junctions, Kinesins genetics, Myosins genetics, Precipitin Tests, Rats, Receptor Protein-Tyrosine Kinases genetics, Receptor, EphA7, Receptor, EphB2, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Substrate Specificity, Transfection, Brain metabolism, Kinesins metabolism, Myosins metabolism, Receptor Protein-Tyrosine Kinases metabolism
- Abstract
The AF-6/afadin protein, which contains a single PDZ domain, forms a peripheral component of cell membranes at specialized sites of cell-cell junctions. To identify potential receptor-binding targets of AF-6 we screened the PDZ domain of AF-6 against a range of COOH-terminal peptides selected from receptors having potential PDZ domain-binding termini. The PDZ domain of AF-6 interacts with a subset of members of the Eph subfamily of RTKs via its COOH terminus both in vitro and in vivo. Cotransfection of a green fluorescent protein-tagged AF-6 fusion protein with full-length Eph receptors into heterologous cells induces a clustering of the Eph receptors and AF-6 at sites of cell-cell contact. Immunohistochemical analysis in the adult rat brain reveals coclustering of AF-6 with Eph receptors at postsynaptic membrane sites of excitatory synapses in the hippocampus. Furthermore, AF-6 is a substrate for a subgroup of Eph receptors and phosphorylation of AF-6 is dependent on a functional kinase domain of the receptor. The physical interaction of endogenous AF-6 with Eph receptors is demonstrated by coimmunoprecipitation from whole rat brain lysates. AF-6 is a candidate for mediating the clustering of Eph receptors at postsynaptic specializations in the adult rat brain.
- Published
- 1999
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