title: Fluorescent saxitoxins for live cell imaging of single voltage-gated sodium ion channels beyond the optical diffraction limit.
abstract: A desire to better understand the role of voltage-gated sodium channels (Na(V)s) in signal conduction and their dysregulation in specific disease states motivates the development of high precision tools for their study. Nature has evolved a collection of small molecule agents, including the shellfish poison (+)-saxitoxin, that bind to the extracellular pore of select Na(V) isoforms. As described in this report, de novo chemical synthesis has enabled the preparation of fluorescently labeled derivatives of (+)-saxitoxin, STX-Cy5, and STX-DCDHF, which display reversible binding to Na(V)s in live cells. Electrophysiology and confocal fluorescence microscopy studies confirm that these STX-based dyes function as potent and selective Na(V) labels. The utility of these probes is underscored in single-molecule and super-resolution imaging experiments, which reveal Na(V) distributions well beyond the optical diffraction limit in subcellular features such as neuritic spines and filopodia.
authors: Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, CA 94305-5080, USA.
authors: Alison E
authors: AE
authors: Ondrus
authors: Hsiao-lu D
authors: HL
authors: Lee
authors: Shigeki
authors: S
authors: Iwanaga
authors: William H
authors: WH
authors: Parsons
authors: Brian M
authors: BM
authors: Andresen
authors: W E
authors: WE
authors: Moerner
authors: J
authors: J
authors: Du Bois
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D018613:Microscopy, Confocal; D008958:Models, Molecular; D015394:Molecular Structure; D016716:PC12 Cells; D051381:Rats; D012530:Saxitoxin / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*; D015222:Sodium Channels / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D005456:Fluorescent Dyes; D015222:Sodium Channels; D012530:Saxitoxin