Stapled Voltage-Gated Calcium Channel (CaV) ?-Interaction Domain (AID) Peptides Act As Selective Protein-Protein Interaction Inhibitors of CaV Function.

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 ?-interaction domain (AID) and cytoplasmic ?-subunit (CaV?). 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:CaV? interactions and reduce the entropic penalty associated with AID binding to CaV?. Importantly, electrophysiological studies reveal that stapled AID peptides act as effective inhibitors of the CaV?1:CaV? interaction that modulate CaV function in an CaV? 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 CaV modulator design.

SUBMITTER: Findeisen F 

PROVIDER: S-EPMC5481814 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature