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 language | English |
---|---|
Pages (from-to) | 4311-21 |
Number of pages | 11 |
Journal | British Journal of Pharmacology |
Volume | 171 |
Issue number | 18 |
DOIs | |
Publication status | Published - 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