TMEM16A channels generate Ca 2+ -activated Cl − currents in cerebral artery smooth muscle cells

作者：Candice M. Thomas-Gatewood, Zachary P. Neeb, Simon Bulley, Adebowale Adebiyi, John P. Bannister, M. Dennis Leo, Jonathan H. Jaggar · 发表于：American Journal of Physiology-Heart and Circulatory Physiology · 年份：2011 · DOI：10.1152/ajpheart.00404.2011 · 被引用次数：110 · 研究领域：Ion channel regulation and function、Neuroscience and Neuropharmacology Research、Ion Channels and Receptors

Transmembrane protein (TMEM)16A channels are recently discovered membrane proteins that display electrophysiological properties similar to classic Ca(2+)-activated Cl(-) (Cl(Ca)) channels in native cells. The molecular identity of proteins that generate Cl(Ca) currents in smooth muscle cells (SMCs) of resistance-size arteries is unclear. Similarly, whether cerebral artery SMCs generate Cl(Ca) currents is controversial. Here, using molecular biology and patch-clamp electrophysiology, we examined TMEM16A channel expression and characterized Cl(-) currents in arterial SMCs of resistance-size rat cerebral arteries. RT-PCR amplified transcripts for TMEM16A but not TMEM16B-TMEM16H, TMEM16J, or TMEM16K family members in isolated pure cerebral artery SMCs. Western blot analysis using an antibody that recognized recombinant (r)TMEM16A channels detected TMEM16A protein in cerebral artery lysates. Arterial surface biotinylation and immunofluorescence indicated that TMEM16A channels are located primarily within the arterial SMC plasma membrane. Whole cell Cl(Ca) currents in arterial SMCs displayed properties similar to those generated by rTMEM16A channels, including Ca(2+) dependence, current-voltage relationship linearization by an elevation in intracellular Ca(2+) concentration, a Nerstian shift in reversal potential induced by reducing the extracellular Cl(-) concentration, and a negative reversal potential shift when substituting extracellular I(-) for Cl(-). A pore-targeting TMEM16A...