Portability of paddle motif function and pharmacology in voltage sensors

• Published in: Nature Vol. 450; no. 7168; pp. 370 - 375
• Main Authors: Kim, Jae Il, Jung, Hoi Jong, Swartz, Kenton J, Alabi, AbdulRasheed A, Bahamonde, Maria Isabel
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 15-11-2007; Nature Publishing Group
• Subjects: Amino Acid Motifs; Amino Acid Sequence; Animals; Biological and medical sciences; Cell Line; Cell membranes. Ionic channels. Membrane pores; Cell structures and functions; Cellular biology; Channels; Conserved Sequence; Electric Conductivity; Electric potential; Electricity; Fundamental and applied biological sciences. Psychology; Humans; Ion Channel Gating - drug effects; Ions; Membranes; Models, Molecular; Modular; Molecular and cellular biology; Molecular Sequence Data; Oocytes - metabolism; Paddles; Pharmacology; Potassium Channels, Voltage-Gated - chemistry; Potassium Channels, Voltage-Gated - genetics; Potassium Channels, Voltage-Gated - metabolism; Protein Conformation; Proteins; Rats; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Sensors; Spider Venoms - pharmacology; Toxicology; Toxins; Voltage; Xenopus; Toxin; Membrane protein; Voltage-gated canal; Domain structure; Molecular interaction; Ionic channel; Pharmacology
• ISSN: 0028-0836; 1476-4687; 1476-4679
• DOI: 10.1038/nature06266

Voltage-sensing domains enable membrane proteins to sense and react to changes in membrane voltage. Although identifiable S1-S4 voltage-sensing domains are found in an array of conventional ion channels and in other membrane proteins that lack pore domains, the extent to which their voltage-sensing mechanisms are conserved is unknown. Here we show that the voltage-sensor paddle, a motif composed of S3b and S4 helices, can drive channel opening with membrane depolarization when transplanted from an archaebacterial voltage-activated potassium channel (KvAP) or voltage-sensing domain proteins (Hv1 and Ci-VSP) into eukaryotic voltage-activated potassium channels. Tarantula toxins that partition into membranes can interact with these paddle motifs at the protein-lipid interface and similarly perturb voltage-sensor activation in both ion channels and proteins with a voltage-sensing domain. Our results show that paddle motifs are modular, that their functions are conserved in voltage sensors, and that they move in the relatively unconstrained environment of the lipid membrane. The widespread targeting of voltage-sensor paddles by toxins demonstrates that this modular structural motif is an important pharmacological target.