FIGURE 7.

Model of the predicted role of Tmem16a in murine colonic epithelium. Tmem16a is expressed in both murine intestinal epithelial and goblet cells, predominantly in the basolateral membrane. In adult normal murine large intestine, CFTR is the only apical Cl^– channel and Tmem16a does not directly serve as luminal channel for secretion of Cl^–. Through mechanisms outlined in previous reports (Schreiber et al., 2015; Cabrita et al., 2017), Tmem16a enables compartmentalized Ca²⁺ signals close to apical and basolateral membranes, which support activation of CFTR (apical) and Sk4 Ca²⁺-activated K⁺ channels (basolateral) in fluid secreting cells. In goblet cells it supports apical exocytosis of mucus-filled granules (Benedetto et al., 2019a).