A genetically targetable fluorescent probe of channel gating with rapid kinetics.
We have developed a genetically targetable, optical channel-gating reporter that converts rapid membrane potential changes into changes in fluorescence intensity. We have named this construct SPARC (sodium channel protein-based activity reporting construct). Green fluorescent protein was inserted into an intracellular loop of a reversibly nonconducting form of the rat mu I skeletal muscle voltage-gated sodium channel. Rapid changes of the membrane potential modulate the fluorescence of the inserted green fluorescent protein. This change in fluorescence can faithfully report depolarizing pulses as short as 2 ms. The fluorescence signal does not inactivate during extended depolarizations. Several features of the probe's response properties indicate that it likely reports gating charge movement of a single domain of rat mu I skeletal muscle. This probe provides a new approach for studying rapid channel movements and may possibly act as a fluorescent activity reporter in excitable cells.
Ataka
Kazuto
K
The John B. Pierce Laboratory, Interdepartmental Neuroscience Program, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06519, USA.
Pieribone
Vincent A
VA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005456:Fluorescent Dyes; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D015640:Ion Channel Gating / Q000235:genetics / Q000502:physiology*; D007700:Kinetics; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics*; D008564:Membrane Potentials / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D051381:Rats; D015222:Sodium Channels / Q000502:physiology*; D014158:Transcription, Genetic
D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D015222:Sodium Channels; D049452:Green Fluorescent Proteins