Open AccessFibroblast growth factor, but not activin, is a potentactivator of mitogen-activated protein kinase in Xenopusexplants.
Author(s) -
Lee M. Graves,
Jennifer L. Northrop,
Brian C. Potts,
Edwin G. Krebs,
David Kimelman
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.5.1662
Subject(s) - mapk/erk pathway , protein kinase a , biology , xenopus , microbiology and biotechnology , mitogen activated protein kinase , kinase , mesoderm , endocrinology , medicine , biochemistry , embryonic stem cell , gene
Isolated explants from the animal hemisphere ofXenopus embryos were incubated with Xenopus basic fibroblast growth factor(XbFGF) or human activin A. XbFGF incubation resulted in the rapid activation ofmitogen-activated protein kinase (MAPK) and ribosomal S6 protein kinase(pp90rsk) in a dose-dependent manner with the highest levels of activationoccurring at 50 ng/ml. Maximal activation occurred within 6-10 min after theaddition of growth factor, and the activity of both kinases declined tounstimulated levels after 30 min. Activin was unable to activate either MAPK orpp90rsk in the Xenopus explants to a substantial level, although it induceddorsal mesoderm better than XbFGF under the same experimental conditions. Theregulatory protein Xwnt-8 did not activate MAPK, nor did it enhance theactivation of MAPK by XbFGF. XbFGF was able to activate MAPK through at leastthe midgastrula stage, suggesting that this family of growth factors may have arole in gastrula-stage events.