title: Structural analysis of calmodulin binding to ion channels demonstrates the role of its plasticity in regulation.
abstract: The Ca²⁺-binding protein calmodulin (CaM) is a well-known regulator of ion-channel activity. Consequently, the Protein Data Bank contains many structures of CaM in complex with different fragments of ion channels that together display a variety of binding modes. In addition to the canonical interaction, in which CaM engages its target with both its domains, many of the ion-channel-CaM complexes demonstrate alternative non-canonical binding modes that depend on the target and experimental conditions. Based on these findings, several mechanisms of ion-channel regulation by CaM have been proposed, all exploiting its plasticity and flexibility in interacting with its targets. In this review, we focus on complexes of CaM with either the voltage-gated calcium channels; the voltage-gated sodium channels or the small conductance calcium-activated potassium channels, for which both structural and functional data are available. For each channel, the functional relevance of these structural data and possible mechanism of calcium-dependent (in)activation and/or facilitation are discussed in detail.
authors.affiliation: Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein Zuid 26-28, Nijmegen, 6525, GA, The Netherlands.
authors.forename: Nadezda V
authors.initials: NV
authors.lastname: Kovalevskaya
authors.forename: Michiel
authors.initials: M
authors.lastname: van de Waterbeemd
authors.forename: Fedir M
authors.initials: FM
authors.lastname: Bokhovchuk
authors.forename: Neil
authors.initials: N
authors.lastname: Bate
authors.forename: René J M
authors.initials: RJ
authors.lastname: Bindels
authors.forename: Joost G J
authors.initials: JG
authors.lastname: Hoenderop
authors.forename: Geerten W
authors.initials: GW
authors.lastname: Vuister
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D015220:Calcium Channels; D002147:Calmodulin; D015221:Potassium Channels