Members of the peripheral membrane-associated guanylate kinase (MAGUK) family function in tumor suppression and receptor clustering by forming multiprotein complexes containing distinct sets of transmembrane, cytoskeletal, and cytoplasmic signaling proteins.

All MAGUKs contain a PDZ-SH3-GUK core and are divided into 4 subfamilies, DLG-like, ZO1-like, p55-like, and LIN2-like, based on their size and the presence of additional domains (Tseng et al., 2001).

MPP5 is a member of the p55-like MAGUK subfamily.The International Radiation Hybrid Mapping Consortium mapped the MPP5 gene to chromosome 14 . Kamberov et al. (2000) mapped the mouse Pals1 gene to chromosome 12.