This gene encodes a member of the Na+/H+ exchanger (NHE) family of integral membrane transporter proteins. The encoded protein is expressed on the apical membrane of the intestinal epithelial cells and plays an important role in mucosal protection. Loss of the encoded protein in mice results in a decrease in the number of goblet and mucin-positive cells, disorganization of the mucin layer, and a decrease in mucosal pH in the colon. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Jan 2015]