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.
Subcellular locations: Apical cell membrane, Cell projection, Microvillus membrane
Highest expression in kidney, liver, colon and small intestine. In kidney, expressed apically along brush border of proximal convoluted tubule but not in cortical collecting ducts. Isoform 1 is expressed primarily in adult small intestine and colon. Isoform 2 is highly expressed in fetal liver . Expressed in duodenum with higher expression in enterocytes along the villus axis and lower expression in crypts (at protein level) .