Presence of the Kv1.5 K(+) channel in the sinoatrial node.
The aim of this study was to establish, using immunolabeling, whether the Kv1.5 K(+) channel is present in the pacemaker of the heart, the sinoatrial (SA) node. In the atrial muscle surrounding the SA node and in the SA node itself (from guinea pig and ferret), Western blotting analysis showed a major band of the expected molecular weight, approximately 64 kD. Confocal microscopy and immunofluorescence labeling showed Kv1.5 labeling clustered in atrial muscle but punctate in the SA node. In atrial muscle, Kv1.5 labeling was closely associated with labeling of Cx43 (gap junction protein) and DPI/II (desmosomal protein), whereas in SA node Kv1.5 labeling was closely associated with labeling of DPI/II but not labeling of Cx43 (absent in the SA node) or Cx45 (another gap junction protein present in the SA node). Electron microscopy and immunogold labeling showed that the Kv1.5 labeling in atrial muscle is preferentially associated with desmosomes rather than gap junctions.
Dobrzynski
H
H
School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.
Rothery
S M
SM
Marples
D D
DD
Coppen
S R
SR
Takagishi
Y
Y
Honjo
H
H
Tamkun
M M
MM
Henderson
Z
Z
Kodama
I
I
Severs
N J
NJ
Boyett
M R
MR
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002417:Cattle; D018031:Connexin 43 / Q000032:analysis; D017630:Connexins / Q000032:analysis; D003598:Cytoskeletal Proteins / Q000032:analysis; D051180:Desmoplakins; D005260:Female; D005289:Ferrets; D019084:Fluorescent Antibody Technique, Indirect; D006168:Guinea Pigs; D006801:Humans; D051666:Kv1.5 Potassium Channel; D008297:Male; D051379:Mice; D015221:Potassium Channels / Q000032:analysis*; D024642:Potassium Channels, Voltage-Gated; D012849:Sinoatrial Node / Q000737:chemistry*; D013347:Subcellular Fractions
D018031:Connexin 43; D017630:Connexins; D003598:Cytoskeletal Proteins; D051180:Desmoplakins; C496981:KCNA5 protein, human; C496982:Kcna5 protein, mouse; D051666:Kv1.5 Potassium Channel; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; C082920:connexin 45