Functions of ANO1/TMEM16A, Ca2+-activated Cl- channels inRegulation of Blood Pressure and Vascular Remodeling

Since the molecule of Ca2+-activated Cl- channels (CaCC) had been identified as ANO1, major progresses have been made in recent studies on its roles in vascular functions. ANO1 has been confirmed to represent the CaCC channels in vascular smooth myocytes (VSMCs). Generally, ANO1 expresses more in resistance-size small arteries. When activated, it functions to control the VSMC membrane potentials by depolarization. As a result, the voltage-dependent Ca2+ channel is opened, leading to Ca2+ entry and VSMC contraction. Thus, the function of ANO1 is important for maintenance of normal blood pressure. Under influence of agonists, e.g., angiotensin II, ANO1 also participates in VSMC differentiation and remodeling which are mediated by KLF5, myocardin and SRF. The factors regulate the transcription of the ANO1 gene and other genes for VSMC differentiation and proliferation.