MPP7 acts as an important adapter that promotes epithelial cell polarity and tight junction formation via its interaction with DLG1. MPP7 is involved in the assembly of protein complexes at sites of cell-cell contact.Membrane-associated guanylate kinases (MAGUKs) are important adaptor proteins involved in the assembly of protein complexes at sites of cell-cell contact. They are found in synapses, adherens junctions, and tight junctions. All MAGUKs contain at least 1 PDZ domain, an SH3 domain, and a GUK domain, and many contain 1 or 2 L27 domains, which are involved in multimerization of MAGUKs. MPP7 belongs to the p55 stardust subfamily of MAGUKs, which is named for a Drosophila gene required for establishment of cell polarity in the developing fly embryo (Bohl et al., 2007 [PubMed 17237226]).