Interaction of the tumor suppressor PTEN/MMAC with a PDZ domain of MAGI3, a novel membrane-associated guanylate kinase.

PTEN/MMAC is a phosphatase that is mutated in multiple human tumors. PTEN/MMAC dephosphorylates 3-phosphorylated phosphatidylinositol phosphates that activate AKT/protein kinase B (PKB) kinase activity. AKT/PKB is implicated in the inhibition of apoptosis, and cell lines and tumors with mutated PTEN/MMAC show increased AKT/PKB kinase activity and resistance to apoptosis. PTEN/MMAC ...
contains a PDZ domain-binding site, and we show here that the phosphatase binds to a PDZ domain of membrane-associated guanylate kinase with inverted orientation (MAGI) 3, a novel inverted membrane-associated guanylate kinase that localizes to epithelial cell tight junctions. Importantly, MAGI3 and PTEN/MMAC cooperate to modulate the kinase activity of AKT/PKB. These data suggest that MAGI3 allows for the juxtaposition of PTEN/MMAC to phospholipid signaling pathways involved with cell survival.
Mesh Terms:
Amino Acid Sequence, Animals, Binding Sites, Cell Line, Conserved Sequence, Epithelial Cells, Female, Genes, Suppressor, Guanylate Kinase, Humans, Male, Membrane Proteins, Molecular Sequence Data, Nucleoside-Phosphate Kinase, Organ Specificity, PTEN Phosphohydrolase, Phosphoric Monoester Hydrolases, Recombinant Proteins, Saccharomyces cerevisiae, Sequence Alignment, Sequence Homology, Amino Acid, Tight Junctions, Tumor Cells, Cultured, Tumor Suppressor Proteins
J. Biol. Chem.
Date: Jul. 14, 2000
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