Characterization of intracellular signals via tyrosine 1062 in RET activated by glial cell line-derived neurotrophic factor

Abstract

Glial cell line derived neurotrophic factor (GDNF) signals through a multicomponent receptor complex consisting of RET receptor tyrosine kinase and a member of GDNF family receptor a (GFRa). Recently, it was shown that tyrosine 1062 in RET represents a binding site for SHC adaptor proteins and is crucial for both RAS/mitogen activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3-K)/AKT signaling pathways. In the present study, we characterized how these two pathways diverge from tyrosine 1062, using human neuroblastoma and primitive neuroectodermal tumor cell lines expressing RET at high levels. In response to GDNF stimulation, SHC bound to GAB1 and GRB2 adaptor proteins as well as RET, and SHC and GAB1 were highly phosphorylated on tyrosine. The complex formation consisting of SHC, GAB1 and GRB2 was almost abolished by replacement of tyrosine 1062 in RET with phenylalanine. Tyrosine-phosphorylated GAB1 was also associated with p85 subunit of PI3-K, resulting in PI3-K and AKT activation, whereas SHC-GRB2-SOS complex was responsible for the RAS/ERK signaling pathway. These results suggested that the RAS and PI3-K pathways activated by GDNF bifurcate mainly through SHC bound to tyrosine 1062 in RET. Furthermore, using luciferase reporter-gene assays, we found that the RAS/ERK and PI3-K signaling pathways are important for activation of CREB and NF-kB in GDNF-treated cells, respectively. Oncogene (2000) 19, 4469 ± 4475.

Identification of SNT/FRS2 docking site on RET receptor tyrosine kinase and its role for signal transduction

“…We and others recently demonstrated that a variety of intracellular signals such as the RAS/MAPK and PI3-K/AKT pathways are transduced through tyrosine 1062 in the carboxy-terminal tail of RET (Hayashi et al, 2000;Segou n-Cariou and Billaud, 2000;De Vita et al, 2000;Besset et al, 2000). In addition, we found that the signaling through tyrosine 1062 is critical for transforming activity of all multiple endocrine neoplasia (MEN) 2 mutant forms of RET Ishiguro et al, 1999;Iwashita et al, 1999Iwashita et al, , 2000.…”

Effects of P2Y1 receptor on glial fibrillary acidic protein and glial cell line-derived neurotrophic factor production of astrocytes under ischemic condition and the related signaling pathways

“…GDNF stimulation can induce the activation of signaling molecules PI3-K/ Akt, Ras/ERK, and CREB, etc. [35][36][37] . CREB plays a key role in transcriptional regulation of GDNF expression [38] .…”

Gdnf signaling pathways within the mammalian spermatogonial stem cell niche

“…These residues can serve as intracellular docking sites to many different SH2 domain-containing proteins, including Src. While Src interacts with Ret at Tyr 981 (Encinas et al, 2004), Tyr 1062 serves as a docking site to most other effectors and triggers the activation of the Ras signaling pathway in the developing enteric nervous system, the developing kidney, and also in neuroblastoma (Worby et al, 1996;Jijiwa et al, 2004;Hayashi et al, 2000). Therefore, we examined whether Gdnf can activate Ras signaling in SSCs (He et al, 2008).…”