PALS1/MPP5 Antibody

MPP5 (Membrane Palmitoylated Protein 5; also PALS1/Proteins Associated with Lin7 #1) is a 70-80 kDa member of MAGUK (Membrane-Associated Guanylate Kinase) family of proteins. It is ubiquitously expressed, and plays a key role in the creation of cell polarity and adhesion. Although not its only function, MPP5 is essential for tight junction integrity. Crumbs proteins (Crb-1 and -3) are apically-oriented, integral membrane proteins. These transmembrane proteins are known to bind to cytosolic MPP5, which, in turn, links to PATJ, which, in turn, binds to either cytosolic ZO-3, or to 4-transmembrane laterally-embedded claudin-1. Subsequent binding of ZO-3 with actin unite the cytoskeleton with the cell membrane. Human MPP5 is 675 amino acids (aa) in length. It contains a utilized phosphorylation site at Ser25, two consecutive L27 domains (aa 120-177 and 179-235) that bind PATJ, one PDZ domain (aa 256-336) that binds crumb proteins, an SH3 region (aa 345-417), and a C‑terminal guanylate kinase-like domain (aa 479-660). MPP5 forms both homodimers and heterodimers with MPP4. There is one splice variant that utilizes an alternative start site at Met35. Over aa 392-509, human and mouse MPP5 are identical in amino acid sequence. Overall, human and mouse MPP5 share 97% aa sequence identity.