Nodal signaling uses activin and transforming growth factor-beta receptor-regulated Smads.
Nodal, a member of the transforming growth factor beta (TGF-beta) superfamily, is implicated in many events critical to the early vertebrate embryo, including mesoderm formation, anterior patterning, and left-right axis specification. Here we define the intracellular signaling pathway induced by recombinant nodal protein treatment of P19 embryonal carcinoma cells. Nodal signaling activates pAR3-Lux, a luciferase reporter previously shown to respond specifically to activin and TGF-beta. However, nodal is unable to induce pTlx2-Lux, a reporter specifically responsive to bone morphogenetic proteins. We also demonstrate that nodal induces p(CAGA)(12), a reporter previously shown to be specifically activated by Smad3. Expression of a dominant negative Smad2 significantly reduces the level of luciferase reporter activity induced by nodal treatment. Finally, we show that nodal signaling rapidly leads to the phosphorylation of Smad2. These results provide the first direct biochemical evidence that nodal signaling is mediated by both activin-TGF-beta pathway Smads, Smad2 and Smad3. We also show here that the extracellular cripto protein is required for nodal signaling, making it distinct from activin or TGF-beta signaling.
Kumar
A
A
Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Novoselov
V
V
Celeste
A J
AJ
Wolfman
N M
NM
ten Dijke
P
P
Kuehn
M R
MR
D028341:Activins; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D054278:Embryonal Carcinoma Stem Cells; D004815:Epidermal Growth Factor / Q000502:physiology; D058851:GPI-Linked Proteins; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D017930:Genes, Reporter; D006133:Growth Substances / Q000378:metabolism; D018398:Homeodomain Proteins; D006801:Humans; D007265:Inhibins / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000378:metabolism; D055457:Nodal Protein; D010766:Phosphorylation / Q000187:drug effects; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D051899:Smad2 Protein; D051900:Smad3 Protein; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D029867:Xenopus Proteins
D019485:Bone Morphogenetic Proteins; C491268:CFC1 protein, human; C104433:Cfc1 protein, mouse; D004268:DNA-Binding Proteins; D058851:GPI-Linked Proteins; D006133:Growth Substances; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C526007:NODAL protein, human; D009363:Neoplasm Proteins; D055457:Nodal Protein; C526008:Nodal protein, mouse; D018125:Receptors, Transforming Growth Factor beta; D011994:Recombinant Proteins; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; C070636:TDGF1 protein, human; C489450:Tdgf1 protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; C096788:tdgf1.3 protein, Xenopus; D028341:Activins; D007265:Inhibins; D004815:Epidermal Growth Factor