title: MEKK4 mediates differentiation in response to retinoic acid via activation of c-Jun N-terminal kinase in rat embryonal carcinoma P19 cells.
abstract: Differentiation of P19 embryonal carcinoma cells in response to the morphogen retinoic acid is regulated by Galpha(12/13) and is associated with activation of c-Jun N-terminal kinase. The role of MEKK1 and MEKK4 upstream of the c-Jun N-terminal kinase was investigated in P19 cells. P19 clones stably expressing constitutively active and dominant negative mutants of MEKK1 and MEKK4 were created and characterized. Expression of the constitutively active form of either MEKK1 or MEKK4 mimicked the action of retinoic acid, inducing these embryonal carcinoma cells to primitive endoderm. Expression of the dominant negative form of MEKK1 had no influence on the ability of retinoic acid to induce either JNK activation or primitive endoderm formation in P19 stem cells. Expression of the dominant negative form of MEKK4, in contrast, effectively blocks both morphogen-induced activation of JNK and cellular differentiation. These data identify MEKK4 as upstream of c-Jun N-terminal kinase in the pathway mediating differentiation of P19 stem cells to primitive endoderm.
authors.affiliation: Department of Molecular Pharmacology, University Medical Center, SUNY/Stony Brook, Stony Brook, New York 11794-8651, USA.
authors.forename: J
authors.initials: J
authors.lastname: Kanungo
authors.forename: I
authors.initials: I
authors.lastname: Potapova
authors.forename: C C
authors.initials: CC
authors.lastname: Malbon
authors.forename: H y
authors.initials: Hy
authors.lastname: Wang
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology* / Q000187:drug effects; D018236:Carcinoma, Embryonal; D002454:Cell Differentiation; D004707:Endoderm / Q000166:cytology*; D004789:Enzyme Activation; D048031:JNK Mitogen-Activated Protein Kinases; D048768:MAP Kinase Kinase Kinase 4; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D011994:Recombinant Proteins; D014212:Tretinoin; D017346:Protein Serine-Threonine Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048768:MAP Kinase Kinase Kinase 4; D020930:MAP Kinase Kinase Kinases