Xenopus FRS2 is involved in early embryogenesis in cooperation with the Src family kinase Laloo.
FRS2 has been identified in mammalian cells as a protein that is tyrosine phosphorylated and binds to Grb2 and Shp2 in response to fibroblast growth factor (FGF) or nerve growth factor (NGF) stimulation. But neither its existence in other vertebrate classes or invertebrates nor its function during embryonic development has been defined. Here we have identified and characterized a Xenopus homolog of FRS2 (xFRS2). xFRS2 is tyrosine phosphorylated in early embryos, and overexpression of an unphosphorylatable form of xFRS2 interferes with FGF-dependent mesoderm formation. The Src family kinase Laloo, which was shown to function in FGF signaling during early Xenopus development, binds to xFRS2 and promotes tyrosine phosphorylation of xFRS2. Moreover, xFRS2 and Laloo are shown to bind to Xenopus FGF receptor 1. These results suggest that xFRS2 plays an important role in FGF signaling in cooperation with Laloo during embryonic development.
Kusakabe
M
M
Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Masuyama
N
N
Hanafusa
H
H
Nishida
E
E
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning / Q000502:physiology; D003001:Cloning, Molecular; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development; D005346:Fibroblast Growth Factors / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction / Q000502:physiology*; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology* / Q000378:metabolism; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C440489:FRS2 protein, Xenopus; C106534:FRS2 protein, human; C114358:HCK protein, Xenopus; D046911:Macromolecular Substances; D008565:Membrane Proteins; D010750:Phosphoproteins; D017468:Receptors, Fibroblast Growth Factor; D029867:Xenopus Proteins; D005346:Fibroblast Growth Factors; D019061:src-Family Kinases