Association of beta-catenin with the alpha-subunit of neuronal large-conductance Ca2+-activated K+ channels.
The association of Ca(2+)-activated K(+) channels with voltage-gated Ca(2+) channels at the presynaptic active zones of hair cells, photoreceptors, and neurons contributes to rapid repolarization of the membrane after excitation. Ca(2+) channels have been shown to bind to a large set of synaptic proteins, but the proteins interacting with Ca(2+)-activated K(+) channels remain unknown. Here, we report that the large-conductance Ca(2+)-activated K(+) channel of the chicken's cochlear hair cell interacts with beta-catenin. Yeast two-hybrid assays identified the S10 region of the K(+) channel's alpha-subunit and the ninth armadillo repeat and carboxyl terminus of beta-catenin as necessary for the interaction. An antiserum directed against the alpha-subunit specifically coprecipitated beta-catenin from brain synaptic proteins. beta-Catenin is known to associate with the synaptic protein Lin7/Velis/MALS, whose interaction partner Lin2/CASK also binds voltage-gated Ca(2+) channels. beta-Catenin may therefore provide a physical link between the two types of channels at the presynaptic active zone.
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Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10021, USA.
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Hudspeth
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D000818:Animals; D002645:Chickens; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D051176:beta Catenin
D003598:Cytoskeletal Proteins; D024681:Potassium Channels, Calcium-Activated; D015534:Trans-Activators; D051176:beta Catenin