High impact information on MPP5

• Similarly, overexpression of Par6 in MDCK cells inhibits localization of PALS1 to the tight junction [1].
• One of these protein complexes is the PATJ/PALS1/Crumbs tripartite complex, which is crucial for the establishment and maintenance of cell polarity [2].
• Mammalian Lin-7 forms a complex with several proteins, including PALS1, that have a role in polarity determination in epithelial cells [3].
• Taken together, these results indicate that Lin-7 functions in tight junction formation by stabilizing its membrane-associated guanylate kinase binding partner PALS1 [3].
• Furthermore, exogenously expressed PALS1, but not other Lin-7 binding partners, also rescued the effects of Lin-7 knock down, including the restoration of PATJ protein in rescued cell lines [3].

Biological context of MPP5

• Autoimmunity induced by the graft-versus-host reaction is an experimental model that illustrates this potential mechanism (A. G. Rolink, S. T. Pals, and E. Gleichmann, J. Exp. Med. 157, 755, 1983; R. A. Eisenberg, S. Y. Craven, and P. L. Cohen, Arth. Rheum. 26, S19, 1983) [4].

Anatomical context of MPP5

• While MPP4 is a component of the synaptic terminals of photoreceptors, MPP5 exclusively localizes to apical membrane domains of the outer limiting membrane (OLM) junctions [5].
• MPP4 and MPP5 are closely related members of the p55-subfamily of membrane-associated guanylate kinases (MAGUKs) known to mediate the assembly of protein complexes at the plasma membrane of cell-cell junctions [5].
• PALS1 specifies the localization of ezrin to the apical membrane of gastric parietal cells [6].

Physical interactions of MPP5

• Our biochemical study verifies that ezrin binds to PALS1 via its N terminus and is co-localized with PALS1 to the apical membrane of gastric parietal cells [6].

Co-localisations of MPP5

• Localization studies in human retinae revealed that MPP3 colocalized with MPP5 and CRB1 at the subapical region [7].

Other interactions of MPP5

• Localization studies in the retina showed that CRB1, MPP5, and MPP4 colocalize at the outer limiting membrane (OLM) [8].
• The knock down of Lin-7 also resulted in the loss of expression of several Lin-7 binding partners, including PALS1 and the polarity protein PATJ [3].
• MPP3 is recruited to the MPP5 protein scaffold at the retinal outer limiting membrane [7].
• Finally, our study demonstrates the essential role of ezrin-PALS1 interaction in the apical membrane remodeling associated with parietal cell secretion [6].

Analytical, diagnostic and therapeutic context of MPP5

• Immunofluorescence microscopy reveals extensive colocalization of Veli3 with both MPP4 and MPP5 [5].

References