+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Differential distribution of Kir2.1 and Kir2.3 subunits in canine atrium and ventricle

Differential distribution of Kir2.1 and Kir2.3 subunits in canine atrium and ventricle

American Journal of Physiology. Heart and Circulatory Physiology 283(3): H1123

Ventricular inward rectifier K(+) current (I(K1)) is substantially larger than atrial, producing functionally important action potential differences. To evaluate possible molecular mechanisms, we recorded I(K1) with patch-clamp techniques and studied Kir2.1 and Kir2.3 subunit expression. I(K1) density was >10-fold larger in the canine ventricle than atrium. Kir2.1 protein expression (Western blot) was 78% greater (P < 0.01) in the ventricle, but Kir2.3 band density was 228% greater (P < 0.01) in the atrium. Immunocytochemistry showed transverse tubular localization of Kir2.1 in 89% (17 of 19) of ventricular and 26% (5 of 19, P < 0.0001) of atrial cells. Both exhibited a weakly positive Kir2.1 signal at intercalated disks. Kir2.3 was strongly expressed at the intercalated disks in all cells and in the transverse tubular regions in 78% (14 of 18) of atrial and 22% (4 of 18, P < 0.001) of ventricular cells. Tissue immunohistochemical results qualitatively resembled isolated cell data. We conclude that the expression density and subcellular localization of Kir2.1 and Kir2.3 subunits differ in the canine atrium versus ventricle. Overall protein density differences are insufficient to explain I(K1) discrepancies, which may be related to differences in subcellular distribution.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 010464971

Download citation: RISBibTeXText

PMID: 12181143

DOI: 10.1152/ajpheart.00934.2001

Related references

Kir2.4 and Kir2.1 K(+) channel subunits co-assemble: a potential new contributor to inward rectifier current heterogeneity. Journal of Physiology (Cambridge) 544(2): 337-349, 15 October, 2002

Kir2.3 isoform confers pH sensitivity to heteromeric Kir2.1/Kir2.3 channels in HEK293 cells. Heart Rhythm 4(4): 487-496, 2007

Activation of inwardly rectifying Kir2.x potassium channels by beta 3-adrenoceptors is mediated via different signaling pathways with a predominant role of PKC for Kir2.1 and of PKA for Kir2.2. Naunyn-Schmiedeberg's Archives of Pharmacology 375(5): 311-322, 2007

Differential distribution of individual subunits of strongly inwardly rectifying potassium channels (Kir2 family) in rat brain. Brain Research. Molecular Brain Research 139(1): 63-79, 2005

Human cardiac Kir2.1, but not Kir2.3, channel expression is regulated by Nav1.5. European Heart Journal 34(Suppl 1): P5019-P5019, 2013

Kir2.6 regulates the surface expression of Kir2.x inward rectifier potassium channels. Journal of Biological Chemistry 286(11): 9526-9541, 2011

Cloning and expression of cardiac Kir2.1 and Kir2.2 channels in thermally acclimated rainbow trout. American Journal of Physiology. Regulatory Integrative and Comparative Physiology 292(6): R2328, 2007

Selective Golgi export of Kir2.1 controls the stoichiometry of functional Kir2.x channel heteromers. Journal of Cell Science 118(Pt 9): 1935-1943, 2005

Functional expression of Kir2.x in human aortic endothelial cells: the dominant role of Kir2.2. American Journal of Physiology. Cell Physiology 289(5): C1134-C1144, 2005

Low-affinity spermine block mediating outward currents through Kir2.1 and Kir2.2 inward rectifier potassium channels. Journal of Physiology 583(Pt 3): 891-908, 2007

Kir2 inward rectification-controlled precise and dynamic balances between Kir2 and HCN currents initiate pacemaking activity. Faseb Journal 32(6): 3047-3057, 2018

Kir2.2v: A possible negative regulator of the inwardly rectifying K+ channel Kir2.2. FEBS Letters 386(2-3): 211-214, 1996

Molecular dissection of the inward rectifier potassium current (IK1) in rabbit cardiomyocytes: evidence for heteromeric co-assembly of Kir2.1 and Kir2.2. Journal of Physiology 550(Pt 2): 365-372, 2003

The consequences of disrupting cardiac inwardly rectifying K+ current (IK1) as revealed by the targeted deletion of the murine Kir2.1 and Kir2.2 genes. Journal of Physiology (Cambridge) 533(3): 697-710, 2001

Selective inhibition of inward rectifier K+ channels (Kir2.1 or Kir2.2) abolishes protection by ischemic preconditioning in rabbit ventricular cardiomyocytes. Circulation Research 95(3): 325-332, 2004