title: Stapled Voltage-Gated Calcium Channel (CaV) α-Interaction Domain (AID) Peptides Act As Selective Protein-Protein Interaction Inhibitors of CaVFunction.
abstract: For many voltage-gated ion channels (VGICs), creation of a properly functioning ion channel requires the formation of specific protein-protein interactions between the transmembrane pore-forming subunits and cystoplasmic accessory subunits. Despite the importance of such protein-protein interactions in VGIC function and assembly, their potential as sites for VGIC modulator development has been largely overlooked. Here, we develop meta-xylyl (m-xylyl) stapled peptides that target a prototypic VGIC high affinity protein-protein interaction, the interaction between the voltage-gated calcium channel (CaV) pore-forming subunit α-interaction domain (AID) and cytoplasmic β-subunit (CaVβ). We show using circular dichroism spectroscopy, X-ray crystallography, and isothermal titration calorimetry that the m-xylyl staples enhance AID helix formation are structurally compatible with native-like AID:CaVβ interactions and reduce the entropic penalty associated with AID binding to CaVβ. Importantly, electrophysiological studies reveal that stapled AID peptides act as effective inhibitors of the CaVα1:CaVβ interaction that modulate CaVfunction in an CaVβ isoform-selective manner. Together, our studies provide a proof-of-concept demonstration of the use of protein-protein interaction inhibitors to control VGIC function and point to strategies for improved AID-based CaVmodulator design.
authors.forename: Felix
authors.initials: F
authors.lastname: Findeisen
authors.forename: Marta
authors.initials: M
authors.lastname: Campiglio
authors.forename: Hyunil
authors.initials: H
authors.lastname: Jo
authors.forename: Fayal
authors.initials: F
authors.lastname: Abderemane-Ali
authors.forename: Christine H
authors.initials: CH
authors.lastname: Rumpf
authors.forename: Lianne
authors.initials: L
authors.lastname: Pope
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Rossen
authors.forename: Bernhard E
authors.initials: BE
authors.lastname: Flucher
authors.forename: William F
authors.initials: WF
authors.lastname: DeGrado
authors.affiliation: Molecular Biophysics & Integrated Imaging Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Daniel L
authors.identifier: 0000-0002-5998-4214
authors.initials: DL
authors.lastname: Minor
mesh_terms: D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*; D054730:Protein Interaction Domains and Motifs / Q000187:drug effects*; D021122:Protein Subunits / Q000378:metabolism*
chemical_list: D015220:Calcium Channels; D010455:Peptides; D021122:Protein Subunits
keywords: AID:CaVβ interaction; Voltage-gated calcium channel (CaV); X-ray crystallography; electrophysiology; protein−protein interaction antagonist; stapled peptide