The IQ Motif is Crucial for Ca v 1.1 Function

Ca 2+ ‐dependent modulation via calmodulin, with consensus CaM‐binding IQ motif playing a key role, has been documented for most high‐voltage‐activated Ca 2+ channels. The skeletal muscle Ca v 1.1 also exhibits Ca 2+ ‐/CaM‐dependent modulation. Here, whole‐cell Ca 2+ current, Ca 2+ transient, and ma...

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Bibliographic Details
Published in:BioMed research international 2011-01, Vol.2011 (1)
Main Author: Stroffekova, Katarina
Format: Article
Language:English
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Summary:Ca 2+ ‐dependent modulation via calmodulin, with consensus CaM‐binding IQ motif playing a key role, has been documented for most high‐voltage‐activated Ca 2+ channels. The skeletal muscle Ca v 1.1 also exhibits Ca 2+ ‐/CaM‐dependent modulation. Here, whole‐cell Ca 2+ current, Ca 2+ transient, and maximal, immobilization‐resistant charge movement ( Q max ) recordings were obtained from cultured mouse myotubes, to test a role of IQ motif in function of Ca v 1.1. The effect of introducing mutation (IQ to AA) of IQ motif into Ca v 1.1 was examined. In dysgenic myotubes expressing YFP‐Ca v 1.1 AA , neither Ca 2+ currents nor evoked Ca 2+ transients were detectable. The loss of Ca 2+ current and excitation‐contraction coupling did not appear to be a consequence of defective trafficking to the sarcolemma. The Q max in dysgenic myotubes expressing YFP‐Ca v 1.1 AA was similar to that of normal myotubes. These findings suggest that the IQ motif of the Ca v 1.1 may be an unrecognized site of structural and functional coupling between DHPR and RyR.
ISSN:2314-6133
2314-6141
DOI:10.1155/2011/504649