Diversity of voltage-dependent K+ channels in human pulmonary artery smooth muscle cell

Oleksandr Platoshyn, Carmelle V. Remillard, Ivana Fantozzi, Mehran Mandegar, Tiffany T. Sison, Shen Zhang, Elyssa Burg, Jason X.J. Yuan

Research output: Contribution to journalArticle

51 Scopus citations

Abstract

Electrical excitability, which plays an important role in excitation-contraction coupling in the pulmonary vasculature, is regulated by transmembrane ion flux in pulmonary artery smooth muscle cells (PASMC). This study examined the heterogeneous nature of native voltage-dependent K + channels in human PASMC. Both voltage-gated K+ (K v) currents and Ca2+-activated K+ (K ca) currents were observed and characterized. In cell-attached patches of PASMC bathed in Ca2+-containing solutions, depolarization elicited a wide range of K+ unitary conductances (6-290 pS). When cells were dialyzed with Ca2+-free and K+-containing solutions, depolarization elicited four components of Kv currents in PASMC based on the kinetics of current activation and inactivation. Using RT-PCR, we detected transcripts of 1) 22 Kv channel α-subunits (Kv1.1-1.7, Kv1.10, Kv2.1, Kv3.1, Kv3.3-3.4, Kv4.1-4.2, Kv5.1, Kv 6.1-6.3, Kv9.1, Kv9.3, Kv10.1, and K v11.1), 2) three Kv channel β-subunits (K vβ1-3), 3) four Kca channel α-subunits (Slo-α1 and SK2-SK4), and 4) four Kca channel β-subunits (Kcaβ1-4). Our results show that human PASMC exhibit a variety of voltage-dependent K+ currents with variable kinetics and conductances, which may result from various unique combinations of α- and β-subunits forming the native channels. Functional expression of these channels plays a critical role in the regulation of membrane potential, cytoplasmic Ca2+, and pulmonary vasomotor tone.

Original languageEnglish (US)
Pages (from-to)L226-L238
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume287
Issue number1 31-1
DOIs
StatePublished - Jul 1 2004
Externally publishedYes

Keywords

  • Calcium
  • Calcium-activated potassium channel
  • Heterogeneity
  • Membrane potential
  • Proliferation

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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