The MAGUK Protein MPP7 Binds to the Polarity Protein hDlg1 and Facilitates Epithelial Tight Junction Formation
- 1 May 2007
- journal article
- Published by American Society for Cell Biology (ASCB) in Molecular Biology of the Cell
- Vol. 18 (5), 1744-1755
- https://doi.org/10.1091/mbc.e06-11-0980
Abstract
Three groups of evolutionarily conserved proteins have been implicated in the establishment of epithelial cell polarity: the apically-localized proteins of the Par (Par3-Par6-aPKC-Cdc42) and Crumbs groups (Crb3-PALS1-PATJ) and the basolaterally localized proteins of the Dlg group (Dlg1-Scribble-Lgl). During epithelial morphogenesis, these proteins participate in a complex network of interdependent interactions that define the position and functional organization of adherens junctions and tight junctions. However, the biochemical pathways through which they control polarity are poorly understood. In this study, we identify an interaction between endogenous hDlg1 and MPP7, a previously uncharacterized MAGUK-p55 subfamily member. We find that MPP7 targets to the lateral surface of epithelial cells via its L27N domain, through an interaction with hDlg1. Loss of either hDlg1 or MPP7 from epithelial Caco-2 cells results in a significant defect in the assembly and maintenance of functional tight junctions. We conclude that the formation of a complex between hDlg1 and MPP7 promotes epithelial cell polarity and tight junction formation.Keywords
This publication has 45 references indexed in Scilit:
- A Rich1/Amot Complex Regulates the Cdc42 GTPase and Apical-Polarity Proteins in Epithelial CellsCell, 2006
- The mammalian Scribble polarity protein regulates epithelial cell adhesion and migration through E-cadherinThe Journal of cell biology, 2005
- Molecular control of cell polarity and asymmetric cell division in Drosophila neuroblastsCurrent Opinion in Cell Biology, 2005
- Cdc42 and Par6–PKCζ regulate the spatially localized association of Dlg1 and APC to control cell polarizationThe Journal of cell biology, 2005
- Multiple regions of Crumbs3 are required for tight junction formation in MCF10A cellsJournal of Cell Science, 2005
- aPKC kinase activity is required for the asymmetric differentiation of the premature junctional complex during epithelial cell polarizationJournal of Cell Science, 2002
- hINADl/PATJ, a Homolog of Discs Lost, Interacts with Crumbs and Localizes to Tight Junctions in Human Epithelial CellsOnline Journal of Public Health Informatics, 2002
- The Maguk protein, Pals1, functions as an adapter, linking mammalian homologues of Crumbs and Discs LostThe Journal of cell biology, 2002
- A Novel and Conserved Protein-Protein Interaction Domain of Mammalian Lin-2/CASK Binds and Recruits SAP97 to the Lateral Surface of EpitheliaMolecular and Cellular Biology, 2002
- Drosophila Stardust is a partner of Crumbs in the control of epithelial cell polarityNature, 2001