Anoctamin 1 (ANO1) (TMEM16A)

Anoctamin 1 (ANO1), also known as Transmembrane protein 16A (TMEM16A), is a calcium-activated chloride channel (CaCC) that plays a vital role in transepithelial fluid secretion, smooth muscle excitability, and sensory transduction. It is widely expressed in diverse tissues, including airway and intestinal epithelia, vascular smooth muscle, and the pacemaker interstitial cells of Cajal within the gastrointestinal tract. In respiratory medicine, pharmacological activation of TMEM16A is explored as a mutation-agnostic therapeutic strategy for cystic fibrosis to bypass defective CFTR channels and restore airway hydration. Conversely, TMEM16A is frequently overexpressed in numerous malignancies—such as head and neck squamous cell carcinoma, esophageal cancer, and gastrointestinal stromal tumors (GIST)—where it promotes tumor cell proliferation and metastasis. Consequently, it serves as both a significant biomarker for poor clinical prognosis and a target for inhibitory small-molecule drugs. While various inhibitors and potentiators are in development, achieving high selectivity remains a primary challenge due to the structural similarities among the ten members of the anoctamin family.

Other names

Anoctamin 1ANO1Transmembrane protein 16ATransmembrane member 16ADiscovered on GIST 1DOG1Oral cancer overexpressed 2ORAOV2Tumor-amplified and overexpressed sequence 2TAOS2

The target functions as a calcium-activated chloride channel where drugs act via three primary modalities: pore-blocking inhibitors that physically obstruct ion flow, allosteric modulators that stabilize the channel's closed state to reduce oncogenic signaling or muscle tone, and activators or potentiators that enhance the channel's sensitivity to intracellular calcium to promote chloride-driven fluid secretion.