TMEM16A (also known as anoctamin 1, ANO1) is the molecular basis of the calcium-activated chloride channels (CaCCs). Studies have shown that TMEM16A is involved in regulating fertilization of oocytes, transport of matter across cell membranes, and contraction of smooth muscle. Studies have shown that TMEM16A is associated with the development and progression of several diseases and has the potential to be a drug target for the treatment of asthma, secretory diarrhea, and cancer. CaCC_inh-A01 (A01) is widely recognized as a highly effective inhibitor of TMEM16A channel and has excellent drug-likeness. However, the mechanism of its inhibition of TMEM16A is still elusive. Here, we combined molecular dynamics simulations, mutagenesis with electrophysiological experiments to explore the molecular mechanism how A01 inhibits the activation of TMEM16A. Calculations showed that the binding pocket of A01 is located above the pore and that A01 can bind α4 thus preventing α4 from moving away from α6 in the calcium-bound state, which leads to the pore of TMEM16A channel in the calcium-bound state not opening. Moreover, the carboxyl and amide oxygen atoms of A01 are the key pharmacodynamic groups of A01 to inhibit TMEM16A. Our results provide an aid to the development of A01 as a potential drug for TMEM16A dysfunction-related disorders.
 

TMEM16A,CaCCinh-A01,Inhibitor,CaCCs