A mutation in the beta interaction domain of the Ca(2+) channel alpha(1C) subunit reduces the affinity of the (+)-[(3)H]isradipine binding site.

Monika Hitzl, Jörg Striessnig, Birgit Neuhuber, Bernhard E Flucher

Department of Biochemical Pharmacology, University of Innsbruck, A-6020 Innsbruck, Austria.

FEBS letters 2002 Jul 31

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The molecular mechanisms of how alpha(1) and beta subunits of voltage-gated Ca(2+) channels interact with one another are still controversial. Here we show that despite a mutation in the beta interaction domain that has previously been shown to disrupt binding, alpha(1C)Y467S and beta(1a-myc) still formed immunoprecipitable complexes when coexpressed in tsA201 cells. However, the alpha(1C)Y467S-beta(1a-myc) complexes had a decreased affinity to (+)-[(3)H]isradipine. This indicates that the beta interaction domain in the I-II loop of the alpha(1) subunit is not merely an anchor required for the functional interaction of the two Ca(2+) channel subunits but is itself part of the effector pathway for beta-induced channel modulation.

Citation

Monika Hitzl, Jörg Striessnig, Birgit Neuhuber, Bernhard E Flucher. A mutation in the beta interaction domain of the Ca(2+) channel alpha(1C) subunit reduces the affinity of the (+)-[(3)H]isradipine binding site. FEBS letters. 2002 Jul 31;524(1-3):188-92