Abstract
Mesd is a specialized chaperone for low-density lipoprotein receptor-related protein 5 (LRP5) and LRP6. In our previous studies, we found that Mesd binds to mature LRP6 on the cell surface and blocks the binding of Wnt antagonist Dickkopf-1 (Dkk1) to LRP6. Herein, we demonstrate that Mesd also binds to LRP5 with a high affinity and is a universal inhibitor of LRP5 and LRP6 ligands. Mesd not only blocks binding of Wnt antagonists Dkk1 and Sclerostin to LRP5 and LRP6 but also inhibits Wnt3A and Rspondin1-induced Wnt/beta-catenin signaling in LRP5- and LRP6-expressing cells. We also found that Mesd, Dkk1, and Sclerostin compete with one another for binding to LRP5 and LRP6 at the cell surface. More importantly, we demonstrated that Mesd is able to suppress LRP6 phosphorylation and Wnt/beta-catenin signaling in prostate cancer PC-3 cells and inhibits PC-3 cell proliferation. Our results indicate that recombinant Mesd protein is a useful tool for studying Wnt/beta-catenin signaling on the cell surface and has a potential therapeutic role in Wnt-dependent cancers.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adaptor Proteins, Signal Transducing
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Animals
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Antineoplastic Agents* / pharmacology
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Bone Morphogenetic Proteins / antagonists & inhibitors
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Bone Morphogenetic Proteins / metabolism
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CHO Cells
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Cell Line
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Cell Line, Tumor
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Cell Membrane / metabolism
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Cricetinae
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Cricetulus
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Genetic Markers
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Growth Inhibitors / physiology*
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Humans
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Intercellular Signaling Peptides and Proteins / metabolism
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LDL-Receptor Related Proteins / antagonists & inhibitors*
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LDL-Receptor Related Proteins / biosynthesis
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LDL-Receptor Related Proteins / metabolism
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Low Density Lipoprotein Receptor-Related Protein-5
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Low Density Lipoprotein Receptor-Related Protein-6
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Mice
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Molecular Chaperones / metabolism
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Molecular Chaperones / physiology*
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Protein Binding
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Signal Transduction / physiology*
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Wnt Proteins / antagonists & inhibitors*
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Wnt Proteins / physiology
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beta Catenin / antagonists & inhibitors*
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beta Catenin / physiology
Substances
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Adaptor Proteins, Signal Transducing
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Antineoplastic Agents
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Bone Morphogenetic Proteins
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DKK1 protein, human
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Genetic Markers
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Growth Inhibitors
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Intercellular Signaling Peptides and Proteins
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LDL-Receptor Related Proteins
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LRP5 protein, human
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LRP6 protein, human
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Low Density Lipoprotein Receptor-Related Protein-5
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Low Density Lipoprotein Receptor-Related Protein-6
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Lrp5 protein, mouse
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Lrp6 protein, mouse
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MESD protein, mouse
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Molecular Chaperones
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SOST protein, human
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Wnt Proteins
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beta Catenin