title: alpha-actinin-2 couples to cardiac Kv1.5 channels, regulating current density and channel localization in HEK cells.
abstract: Voltage-gated K(+) (Kv) channels are particularly important in the physiology of excitable cells in the heart and the brain. PSD-95 is known to cluster Shaker channels and NMDA receptors and the latter is known to couple through alpha-actinin-2 to the post-synaptic cytoskeleton [Wyszynski et al. (1997) Nature 385, 439-442], but the mechanisms by which Kv channels are linked to the actin cytoskeleton and clustered at specific sites in the heart are unknown. Here we provide evidence that Kv1.5 channels, widely expressed in the cardiovascular system, bind with alpha-actinin-2. Human Kv1.5 interacts via its N-terminus/core region and can be immunoprecipitated with alpha-actinin-2 both after in vitro translation and from HEK cells expressing both proteins. The ion channels and alpha-actinin-2 co-localize at the membrane in HEK cells, where disruption of the actin cytoskeleton and antisense constructs to alpha-actinin-2 modulate the ion and gating current density.
authors.affiliation: Department of Physiology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, BC, Canada.
authors.forename: N D
authors.initials: ND
authors.lastname: Maruoka
authors.forename: D F
authors.initials: DF
authors.lastname: Steele
authors.forename: B P
authors.initials: BP
authors.lastname: Au
authors.forename: P
authors.initials: P
authors.lastname: Dan
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: E D
authors.initials: ED
authors.lastname: Moore
authors.forename: D
authors.initials: D
authors.lastname: Fedida
mesh_terms: D000185:Actinin / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003572:Cytochalasins / Q000494:pharmacology; D003599:Cytoskeleton / Q000378:metabolism; D016373:DNA, Antisense / Q000494:pharmacology; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D008856:Microscopy, Fluorescence; D009206:Myocardium / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D020798:Two-Hybrid System Techniques
chemical_list: C401401:ACTN2 protein, human; D003572:Cytochalasins; D016373:DNA, Antisense; D010446:Peptide Fragments; D015221:Potassium Channels; D011993:Recombinant Fusion Proteins; D000185:Actinin