Prohibitin is required for Ras-induced Raf-MEK-ERK activation and epithelial cell migration.

Department of Molecular Biology, Max Planck Institute for Infection Biology, Schumannstrasse 21/22, D-10117 Berlin, Germany.
Ras proteins control the signalling pathways that are responsible for normal growth and malignant transformation. Raf protein kinases are direct Ras effector proteins that initiate the mitogen-activated protein kinase (MAPK) cascade, which mediates diverse biological functions such as cell growth, survival and differentiation. Here we show that prohibitin, a ubiquitously expressed and evolutionarily conserved protein is indispensable for the activation of the Raf-MEK-ERK pathway by Ras. The membrane targeting and activation of C-Raf by Ras needs prohibitin in vivo. In addition, direct interaction with prohibitin is required for C-Raf activation. C-Raf kinase fails to interact with the active Ras induced by epidermal growth factor in the absence of prohibitin. Moreover, in prohibitin-deficient cells the adhesion complex proteins cadherin and beta-catenin relocalize to the plasma membrane and thereby stabilize adherens junctions. Our data show an unexpected role of prohibitin in the activation of the Ras-Raf signalling pathway and in modulating epithelial cell adhesion and migration.
Mesh Terms:
14-3-3 Proteins, Cadherins, Caveolae, Cell Adhesion, Cell Line, Tumor, Cell Movement, Cell Shape, Cytoskeletal Proteins, Cytosol, Enzyme Inhibitors, Epidermal Growth Factor, Epithelial Cells, Flavonoids, HeLa Cells, Humans, MAP Kinase Signaling System, Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Mitogen-Activated Protein Kinase 1, Mitogen-Activated Protein Kinase 3, Mitogen-Activated Protein Kinase Kinases, Phosphorylation, Protein Binding, Protein-Serine-Threonine Kinases, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-akt, Proto-Oncogene Proteins c-raf, RNA, Small Interfering, Repressor Proteins, Tetradecanoylphorbol Acetate, Trans-Activators, Transfection, beta Catenin, raf Kinases, ras Proteins
Nat. Cell Biol. Aug. 01, 2005; 7(8);837-43 [PUBMED:16041367]
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