Inhibitory role of phosphatidylinositol 4,5-bisphosphate on TMEM16A-encoded calcium-activated chloride channels in rat pulmonary artery

H. A. T. Pritchard, N. Leblanc, A. P. Albert, I. A. Greenwood

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND AND PURPOSE: Calcium-activated chloride channels (CaCCs) are key depolarizing mechanisms that have an important role in vascular smooth muscle contraction. Here, we investigated whether these channels are regulated by phosphatidylinositol (4,5) bisphosphate [P(4,5)P2 ], a known regulator of various ion channels.

EXPERIMENTAL APPROACH: Calcium-activated Cl(-) currents (IClCa ) were recorded by patch clamp electrophysiology of rat isolated pulmonary artery smooth muscle cells. TMEM16A protein-phosphoinositide interaction was studied by co-immunoprecipitation and phosphoinositide binding arrays on protein lysates from whole pulmonary arteries and HEK293 cells overexpressing TMEM16A, the molecular correlate.

KEY RESULTS: PI(4,5)P2 and other phospholipids were shown to bind directly to TMEM16A isolated from whole pulmonary artery (PA) and TMEM16A-eGFP expressed in HEK293 cells. Agents that reduced PI(4,5)P2 levels through different routes [PLC activation, PI4K inhibition, PI(4,5)P2 scavenging and absorption] all increased IClCa evoked by solutions containing clamped-free [Ca(2+) ], whereas enrichment of activating solutions with PI(4,5)P2 inhibited IClca in PA smooth muscle cells with approximately 50% reduction at 1 μM.

CONCLUSIONS AND IMPLICATIONS: These data are the first to show a negative regulation of TMEM16A-encoded CaCCs by PI(4,5)P2 and propose that control of PI(4,5)P2 levels is a key determinant of arterial physiology.

Original languageEnglish
Pages (from-to)4311-21
Number of pages11
JournalBritish Journal of Pharmacology
Volume171
Issue number18
DOIs
Publication statusPublished - Sept 2014

Keywords

  • Animals
  • Anoctamin-1
  • Chloride Channels/physiology
  • HEK293 Cells
  • Humans
  • Male
  • Mice, Knockout
  • Phosphatidylinositol 4,5-Diphosphate/physiology
  • Pulmonary Artery/cytology
  • Rats, Wistar

Research Beacons, Institutes and Platforms

  • Cathie Marsh Institute

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