Association of β-catenin with the α-subunit of neuronal large-conductance Ca2+-activated K+ channels

  1. F. Lesage*,†,
  2. H. Hibino*,‡, and
  3. A. J. Hudspeth§
  1. Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10021

  1. Contributed by A. J. Hudspeth, November 19, 2003

Abstract

The association of Ca2+-activated K+ channels with voltage-gated Ca2+ channels at the presynaptic active zones of hair cells, photoreceptors, and neurons contributes to rapid repolarization of the membrane after excitation. Ca2+ channels have been shown to bind to a large set of synaptic proteins, but the proteins interacting with Ca2+-activated K+ channels remain unknown. Here, we report that the large-conductance Ca2+-activated K+ channel of the chicken's cochlear hair cell interacts with β-catenin. Yeast two-hybrid assays identified the S10 region of the K+ channel's α-subunit and the ninth armadillo repeat and carboxyl terminus of β-catenin as necessary for the interaction. An antiserum directed against the α-subunit specifically coprecipitated β-catenin from brain synaptic proteins. β-Catenin is known to associate with the synaptic protein Lin7/Velis/MALS, whose interaction partner Lin2/CASK also binds voltage-gated Ca2+ channels. β-Catenin may therefore provide a physical link between the two types of channels at the presynaptic active zone.

Footnotes

  • ↵ § To whom correspondence should be addressed. E-mail: hudspaj{at}rockefeller.edu.

  • ↵ * F.L. and H.H. contributed equally to this work.

  • ↵ † Current address: Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6097, 660 Route des Lucioles, F-06560 Valbonne, France.

  • ↵ ‡ Current address: Department of Pharmacology II, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan.

  • Abbreviations: CaV, voltage-gated Ca2+; slo, slowpoke; cslo, chicken slo; KCa, Ca2+-activated K+; RIM, Rab3-interacting molecule; RBP, RIM-binding protein.

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  1. Published online before print December 30, 2003, doi: 10.1073/pnas.0307681100 PNAS January 13, 2004 vol. 101 no. 2 671-675
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