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In cochlea inner hair cells (IHCs), L-type Ca(2+) channels (LTCCs) formed by alpha1D subunits (D-LTCCs) possess biophysical and pharmacological properties distinct from those of alpha1C containing C-LTCCs. We investigated to which extent these differences are determined by alpha1D itself by analyzing the biophysical and pharmacological properties of cloned(More)
The neuronal L-type calcium channels (LTCCs) Cav1.2alpha1 and Cav1.3alpha1 are functionally distinct. Cav1.3alpha1 activates at lower voltages and inactivates more slowly than Cav1.2alpha1, making it suitable to support sustained L-type Ca2+ inward currents (ICa,L) and serve in pacemaker functions. We compared the biophysical and pharmacological properties(More)
Different types of voltage-gated Ca2+ channels exist in the plasma membrane of electrically excitable cells. By controlling depolarization-induced Ca2+ entry into cells they serve important physiological functions, such as excitation-contraction coupling, neurotransmitter and hormone secretion, and neuronal plasticity. Their function is fine-tuned by a(More)
The specific localization of L-type Ca(2+) channels in skeletal muscle triads is critical for their normal function in excitation-contraction (EC) coupling. Reconstitution of dysgenic myotubes with the skeletal muscle Ca(2+) channel alpha(1S) subunit restores Ca(2+) currents, EC coupling, and the normal localization of alpha(1S) in the triads. In contrast,(More)
At least five different types of voltage-gated Ca2+ channels exist in electrically excitable mammalian cells. Only one type, the family of L-type Ca2+ channels (L channels), contains high-affinity binding domains within their alpha 1-subunits for different chemical classes of drugs (Ca2+ channel antagonists; exemplified by isradipine, verapamil and(More)
We have investigated the functional consequences of three P/Q-type Ca(2+) channel alpha1A (Ca(v)2.1alpha(1)) subunit mutations associated with different forms of ataxia (episodic ataxia type 2 (EA-2), R1279Stop, AY1593/1594D; progressive ataxia (PA), G293R). Mutations were introduced into human alpha1A cDNA and heterologously expressed in Xenopus oocytes or(More)
L-type Ca2+ channels are characterized by their unique sensitivity to organic Ca2+ channel modulators like the 1,4-dihydropyridines (DHPs). To identify molecular motifs mediating DHP sensitivity, we transferred this sensitivity from L-type Ca2+ channels to the DHP-insensitive class A brain Ca2+ channel, BI-2. Expression of chimeras revealed minimum sequence(More)
Expression of cardiac L-type Ca2+ channels in dysgenic myotubes results in large Ca2+ currents and electrically evoked contractions resulting from Ca2+-entry dependent release of Ca2+ from the sarcoplasmic reticulum. By contrast, expression of either P/Q-type or N-type Ca2+ channels in dysgenic myotubes does not result in electrically evoked contractions(More)
During skeletal muscle excitation-contraction (EC) coupling, membrane depolarizations activate the sarcolemmal voltage-gated L-type Ca(2+) channel (Ca(V)1.1). Ca(V)1.1 in turn triggers opening of the sarcoplasmic Ca(2+) release channel (RyR1) via interchannel protein-protein interaction to release Ca(2+) for myofibril contraction. Simultaneously to this EC(More)
The computer program HOWBIG has been developed based on the reciprocal correlation of size to migration distance of DNA in high voltage gradient gel systems (Southern, 1979). For calculation the program automatically chooses three marker bands migrating closest to the calculated band, reducing the error down to approximately 0.5% or less (reciprocal method,(More)