Intermicrovillar adhesion molecule that forms, via its extracellular domain, calcium-dependent heterophilic complexes with CDHR2 on adjacent microvilli. Thereby, controls the packing of microvilli at the apical membrane of epithelial cells. Through its cytoplasmic domain, interacts with microvillus cytoplasmic proteins to form the intermicrovillar adhesion complex/IMAC. This complex plays a central role in microvilli and epithelial brush border differentiation. Part of the IMAC/intermicrovillar adhesion complex/intermicrovillar tip-link complex composed of ANKS4B, MYO7B, USH1C, CDHR2 and CDHR5. Interacts (via cytoplasmic domain) with USH1C and MYO7B; required for proper localization of CDHR5 to microvilli tips and its function in brush border differentiation. Expressed predominantly in kidney. Also detected in lung and small intestine. At embryonic day 19, both maternal and embryonic kidneys express isoform 1 almost exclusively. In the postpartum female and neonate, expression of isoform 2 increases. N- and O-glycosylated.