A helical region in the C terminus of small-conductance Ca2+-activated K+ channels controls assembly with Apo-calmodulin

Ralph Wissmann, Wolfgang Bildl, Heinz Neumann, Andre F. Rivard, Nikolaj Klöcker, Dietmar Weitz, Uwe Schulte, John Adelman, Detlef Bentrop, Bernd Fakler

Research output: Contribution to journalArticle

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Abstract

Small conductance Ca2+-activated potassium (SK) channels underlie the afterhyperpolarization that follows the action potential in many types of central neurons. SK channels are voltage-independent and gated solely by intracellular Ca2+ in the submicromolar range. This high affinity for Ca2+ results from Ca2+-independent association of the SK α-subunit with calmodulin (CaM), a property unique among the large family of potassium channels. Here we report the solution structure of the calmodulin binding domain (CaMBD, residues 396-487 in rat SK2) of SK channels using NMR spectroscopy. The CaMBD exhibits a helical region between residues 423-437, whereas the rest of the molecule lacks stable overall folding. Disruption of the helical domain abolishes constitutive association of CaMBD with Ca2+ free CaM, and results in SK channels that are no longer gated by Ca2+. The results show that the Ca2+-independent CaM-CaMBD interaction, which is crucial for channel function, is at least in part determined by a region different in sequence and structure from other CaM-interacting proteins.

Original languageEnglish (US)
Pages (from-to)4558-4564
Number of pages7
JournalJournal of Biological Chemistry
Volume277
Issue number6
DOIs
StatePublished - Feb 8 2002

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Calcium-Activated Potassium Channels
Calmodulin
Small-Conductance Calcium-Activated Potassium Channels
Potassium Channels
Nuclear magnetic resonance spectroscopy
Action Potentials
Neurons
Rats
Magnetic Resonance Spectroscopy
Molecules
Electric potential
Proteins

ASJC Scopus subject areas

  • Biochemistry

Cite this

A helical region in the C terminus of small-conductance Ca2+-activated K+ channels controls assembly with Apo-calmodulin. / Wissmann, Ralph; Bildl, Wolfgang; Neumann, Heinz; Rivard, Andre F.; Klöcker, Nikolaj; Weitz, Dietmar; Schulte, Uwe; Adelman, John; Bentrop, Detlef; Fakler, Bernd.

In: Journal of Biological Chemistry, Vol. 277, No. 6, 08.02.2002, p. 4558-4564.

Research output: Contribution to journalArticle

Wissmann, R, Bildl, W, Neumann, H, Rivard, AF, Klöcker, N, Weitz, D, Schulte, U, Adelman, J, Bentrop, D & Fakler, B 2002, 'A helical region in the C terminus of small-conductance Ca2+-activated K+ channels controls assembly with Apo-calmodulin', Journal of Biological Chemistry, vol. 277, no. 6, pp. 4558-4564. https://doi.org/10.1074/jbc.M109240200
Wissmann, Ralph ; Bildl, Wolfgang ; Neumann, Heinz ; Rivard, Andre F. ; Klöcker, Nikolaj ; Weitz, Dietmar ; Schulte, Uwe ; Adelman, John ; Bentrop, Detlef ; Fakler, Bernd. / A helical region in the C terminus of small-conductance Ca2+-activated K+ channels controls assembly with Apo-calmodulin. In: Journal of Biological Chemistry. 2002 ; Vol. 277, No. 6. pp. 4558-4564.
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