Expression profile and protein translation of TMEM16A in murine smooth muscle

Recently, overexpression of the genes TMEM16A and TMEM16B has been shown to produce currents qualitatively similar to native Ca2+-activated Cl− currents (IClCa) in vascular smooth muscle. However, there is no information about this new gene family in vascular smooth muscle, where Cl− channels are a major depolarizing mechanism. Qualitatively similar Cl− currents were evoked by a pipette solution containing 500 nM Ca2+ in smooth muscle cells isolated from BALB/c mouse portal vein, thoracic aorta, and carotid artery. Quantitative PCR using SYBR Green chemistry and primers specific for transmembrane protein (TMEM) 16A or the closely related TMEM16B showed TMEM16A expression as follows: portal vein > thoracic aorta > carotid artery > brain. In addition, several alternatively spliced variant transcripts of TMEM16A were detected. In contrast, TMEM16B expression was very low in smooth muscle. Western blot analysis with different antibodies directed against TMEM16A revealed a number of products with a consistent ...