MAGI-1 interacts with beta-catenin and is associated with cell-cell adhesion structures.
The family of membrane-associated guanylate kinases (MAGUK) comprises peripheral membrane proteins involved in the formation of specialized cell-cell junctions. MAGUK proteins possess a conserved domain composition, containing PDZ, guanylate kinase, and SH3 or WW domains. MAGI-1 is a recently identified member of the MAGUK protein family. Three splice variantsof MAGI-1 have been characterized to date, including MAGI-1a, -1b, and -1c. MAGI-1b is predominantly associated with the crude membrane fraction. Here we show that the fifth PDZ domain of MAGI-1b is essential for membrane localization. We have also identified beta-catenin as a potential ligand for this PDZ domain. MAGI-1b forms complexes with beta-catenin and E-cadherin during the formation of cell-cell junctions in MDCK cells. In agreement with this observation, a significant portion of a GFP fusion of MAGI-1b localizes to the basolateral membrane of polarized MDCK cells.
Dobrosotskaya
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Graduate Program in Cell Regulation, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75235, USA. irinadobro@hotmail.com
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D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry; D002448:Cell Adhesion / Q000502:physiology*; D002460:Cell Line; D017124:Conserved Sequence; D003432:Cross-Linking Reagents; D003598:Cytoskeletal Proteins / Q000737:chemistry* / Q000502:physiology*; D004285:Dogs; D051528:Guanylate Kinases; D051379:Mice; D009703:Nucleoside-Phosphate Kinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017384:Sequence Deletion; D015534:Trans-Activators; D014162:Transfection; D051176:beta Catenin
C495267:CTNNB1 protein, mouse; D003432:Cross-Linking Reagents; D003598:Cytoskeletal Proteins; D011994:Recombinant Proteins; D015534:Trans-Activators; D051176:beta Catenin; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases