title: Identification of a functional interaction between Kv4.3 channels and c-Src tyrosine kinase.
abstract: Voltage-gated K(+) (Kv) channels are key determinants of cardiac and neuronal excitability. A substantial body of evidence has accumulated in support of a role for Src family tyrosine kinases in the regulation of Kv channels. In this study, we examined the possibility that c-Src tyrosine kinase participates in the modulation of the transient voltage-dependent K(+) channel Kv4.3. Supporting a mechanistic link between Kv4.3 and c-Src, confocal microscopy analysis of HEK293 cells stably transfected with Kv4.3 showed high degree of co-localization of the two proteins at the plasma membrane. Our results further demonstrate an association between Kv4.3 and c-Src by co-immunoprecipitation and GST pull-down assays, this interaction being mediated by the SH2 and SH3 domains of c-Src. Furthermore, we show that Kv4.3 is tyrosine phosphorylated under basal conditions. The functional relevance of the observed interaction between Kv4.3 and c-Src was established in patch-clamp experiments, where application of the Src inhibitor PP2 caused a decrease in Kv4.3 peak current amplitude, but not the inactive structural analogue PP3. Conversely, intracellular application of recombinant c-Src kinase or the protein tyrosine phosphatase inhibitor bpV(phen) increased Kv4.3 peak current amplitude. In conclusion, our findings provide evidence that c-Src-induced Kv4.3 channel activation involves their association in a macromolecular complex and suggest a role for c-Src-Kv4.3 pathway in regulating cardiac and neuronal excitability.
authors.affiliation: Department of Anesthesiology, Division of Molecular Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA 90095-1778, USA. pgomes@med.up.pt
authors.forename: Pedro
authors.initials: P
authors.lastname: Gomes
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Saito
authors.forename: Cris
authors.initials: C
authors.lastname: Del Corsso
authors.forename: Abderrahmane
authors.initials: A
authors.lastname: Alioua
authors.forename: Mansoureh
authors.initials: M
authors.lastname: Eghbali
authors.forename: Ligia
authors.initials: L
authors.lastname: Toro
authors.forename: Enrico
authors.initials: E
authors.lastname: Stefani
mesh_terms: D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004594:Electrophysiology; D004789:Enzyme Activation; D006801:Humans; D018408:Patch-Clamp Techniques; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D051672:Shal Potassium Channels / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D051672:Shal Potassium Channels; D019000:Phosphotyrosine; D019061:src-Family Kinases