Apo calmodulin binding to the L-type voltage-gated calcium channel Cav1.2 IQ peptide

Lu Yun Lian, Daniel Myatt, Ashraf Kitmitto

    Research output: Contribution to journalArticlepeer-review


    The influx of calcium through the L-type voltage-gated calcium channels (LTCCs) is the trigger for the process of calcium-induced calcium release (CICR) from the sarcoplasmic recticulum, an essential step for cardiac contraction. There are two feedback mechanisms that regulate LTCC activity: calcium-dependent inactivation (CDI) and calcium-dependent facilitation (CDF), both of which are mediated by calmodulin (CaM) binding. The IQ domain (aa 1645-1668) housed within the cytoplasmic domain of the LTCC Cav1.2 subunit has been shown to bind both calcium-loaded (Ca2+CaM ) and calcium-free CaM (apoCaM). Here, we provide new data for the structural basis for the interaction of apoCaM with the IQ peptide using NMR, revealing that the apoCaM C-lobe residues are most significantly perturbed upon complex formation. In addition, we have employed transmission electron microscopy of purified LTCC complexes which shows that both apoCaM and Ca2+CaM can bind to the intact channel. © 2006 Elsevier Inc. All rights reserved.
    Original languageEnglish
    Pages (from-to)565-570
    Number of pages5
    JournalBiochemical and biophysical research communications
    Issue number3
    Publication statusPublished - 16 Feb 2007


    • Apocalmodulin
    • Electron microscopy
    • L-type voltage-gated calcium channels
    • NMR
    • Protein-protein interactions


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