Concerted interaction of TGF-β and GDNF mediates neuronal differentiation.
The glial cell-line derived neurotrophic factor (GDNF) is crucial for ureteric bud morphogenesis, spermatogenesis, and development of the enteric nervous system and is a potent survival factor for various neuronal populations. However, the impact of GDNF, at least on cell survival, was found to depend strongly on the presence of transforming growth factor β (TGF-β). In this study, we investigate the role of TGF-β in GDNF-induced neuronal differentiation. In a cell culture paradigm of N2aGT cells (neuroblastoma cell line), we show that TGF-β signaling localizes the GDNF ligand-binding receptor GFRa1 to the cell surface, which is a known mechanism by which TGF-β is able to facilitate GDNF signaling. TGF-β-mediated GDNF signaling slightly elevated the phosphorylation state of Ret, the canonical coreceptor for the GPI-linked (glycosyl-phosphatidylinositol) GFRa1. On the basis of morphological as well as immunocytological data, we finally show that GDNF-mediated neuronal differentiation is intensified when GDNF and TGF-β act in concert.
Department of Molecular Embryology, University of Freiburg, Freiburg, Germany.
Katalin
K
Zajzon
Felicitas
F
Pröls
Stephan
S
Heermann
D000818:Animals; D019921:Biotinylation; D015153:Blotting, Western; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000494:pharmacology*; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000096:biosynthesis / Q000235:genetics; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D051379:Mice; D016501:Neurites / Q000187:drug effects; D009474:Neurons / Q000502:physiology*; D010766:Phosphorylation; D051096:Proto-Oncogene Proteins c-ret / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D018125:Receptors, Transforming Growth Factor beta / Q000187:drug effects; D051899:Smad2 Protein / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
C494988:Gfra1 protein, mouse; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; C497783:Smad2 protein, mouse; D016212:Transforming Growth Factor beta; D051096:Proto-Oncogene Proteins c-ret