FUNCTION: Acts as an important adapter that promotes epithelial cell polarity and tight junction formation. Involved in the assembly of protein complexes at sites of cell-cell contact (By similarity). {ECO:0000250}. SUBCELLULAR LOCATION: Membrane {ECO:0000250}; Peripheral membrane protein {ECO:0000250}. Cell junction, tight junction {ECO:0000250}. Cell junction, adherens junction {ECO:0000250}. SIMILARITY: Belongs to the MAGUK family. {ECO:0000305}. CAUTION: Was originally thought to be the ortholog of mammalian DLG3. {ECO:0000305|PubMed:10446262}. |