Inward rectifier K+ channel from human heart and brain: Cloning and stable expression in a human cell line

M. D. Ashen, B. O'Rourke, K. A. Kluge, D. C. Johns, G. F. Tomaselli

Research output: Contribution to journalArticle

Abstract

We have cloned the human homologue of the inward rectifier K+ channel from both heart and brain tissue (HHBIRK1). The human clones were identical to each other in their coding regions and were highly homologous to the mouse macrophage (IRK1) channel. The inward rectifier currents from human and mouse clones were characterized using a novel strategy for stable ion channel expression in a human cell line. The permeability of the expressed inwardly rectifying channels was greater for K+ than for Rb+, whereas no current was observed when K+ was replaced by Na+. A prominent time- and voltage- dependent block was observed in the presence of Ba2+, whereas a small decay in the steady-state current was observed with millimolar concentrations of Na+. Single-channel conductances of 49.1 ± 3.3 pS (n = 6) and 40.2 ± 2.5 pS (n = 3) (P = 0.005) were obtained for the HHBIRK1 and IRK1 clones, respectively. These results indicate that sequence dissimilarities between human and mouse inward rectifier K+ channels may have significant functional consequences.

Original languageEnglish (US)
Pages (from-to)H506-H511
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume268
Issue number1 37-1
DOIs
StatePublished - 1995

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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