title: Coordinated activation of autophosphorylation sites in the RET receptor tyrosine kinase: importance of tyrosine 1062 for GDNF mediated neuronal differentiation and survival.
abstract: The catalytic and signaling activities of RET, a tyrosine kinase receptor for glial cell line-derived neurotrophic factor (GDNF), are controlled by the autophosphorylation of several tyrosine residues in the RET cytoplasmic domain. To analyze the phosphorylation state of individual tyrosines, we generated antibodies recognizing specific phosphotyrosine sites involved in the catalytic (Tyr(905)) and downstream signaling (Tyr(1015), Tyr(1062), and Tyr(1096)) activities of this receptor. Stimulation with GDNF induced coordinated phosphorylation of the 4 tyrosine residues in neuronal cell lines and in primary cultures of sympathetic neurons isolated from rat superior cervical ganglia. Neurturin and artemin, two other members of the GDNF ligand family, also induced synchronized phosphorylation of RET tyrosines with kinetics comparable to those observed with GDNF. Tyrosine phosphorylation was maximal 15 min after ligand stimulation, decaying thereafter with similar kinetics in all 4 residues. Co-stimulation with a soluble form of the GFRalpha1 co-receptor potentiated ligand-dependent phosphorylation of different intracellular tyrosines to a similar extent and increased the survival of superior cervical ganglion neurons compared with treatment with GDNF alone. In vivo, high levels of phosphorylated Tyr(905), Tyr(1015), and Tyr(1062) were detected in embryonic mouse dorsal root ganglia, with a sharp decline at early postnatal stages. Protein transduction of anti-Tyr(P)(1062) antibodies into cultured cells reduced activation of MAPKs ERK1 and ERK2 and the AKT kinase in response to GDNF and diminished GDNF-dependent neuronal differentiation and survival of embryonic sensory neurons from the nodose ganglion. These results demonstrate synchronized utilization of individual RET tyrosine residues in neurons in vivo and reveal an important role for RET Tyr(1062) in mediating neuronal survival by GDNF.
authors.affiliation: Division of Molecular Neurobiology, Department of Neuroscience, Karolinska Institute, S-171 77 Stockholm, Sweden.
authors.forename: Muriel
authors.initials: M
authors.lastname: Coulpier
authors.forename: Jonas
authors.initials: J
authors.lastname: Anders
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Ibáñez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology*; D029721:Drosophila Proteins; D004789:Enzyme Activation; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000502:physiology*; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism*; D051096:Proto-Oncogene Proteins c-ret; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; C495039:GDNF protein, human; C494987:GFRA1 protein, human; C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D014443:Tyrosine; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila; C495001:Ret protein, rat