TY - JOUR
T1 - Characterization of Ret-Shc-Grb2 complex induced by GDNF, MEN 2A, and MEN 2B mutations
AU - Ohiwa, Mikinao
AU - Murakami, Hideki
AU - Iwashita, Toshihide
AU - Asai, Naoya
AU - Iwata, Yosuke
AU - Imai, Tsuneo
AU - Funahashi, Hiroomi
AU - Takagi, Hiroshi
AU - Takahashi, Masahide
N1 - Funding Information:
This work was supported in part by grants-in-aid for scienti®c research and for cancer research from the Ministry of Education, Science, and Culture of Japan. We are grateful to J. Aoki and K. Imaizumi for their technical assistance.
PY - 1997/8/28
Y1 - 1997/8/28
N2 - We analyzed the intracellular signalling pathway through Ret activated by glial-cell-line-derived neurotrophic factor (GDNF), multiple endocrine neoplasia (MEN) 2A and 2B mutations. The results showed that all of them induce a signal transducing complex consisting of Ret, Shc, and Grb2 proteins. In addition, GDNF clearly activated a Ras-MAPK pathway in human neuroblastoma cells. Ret is expressed mainly as two isoforms that differ in the carboxy-terminal sequence: a long isoform (1114 amino acids) and a short isoform (1072 amino acids). The long isoform contains the consensus sequence for binding of the Shc PTB domain but not of its SH2 domain, whereas the short isoform has the consensus sequences for binding of both domains. In vitro binding assay revealed that the long isoform of the MEN2A-Ret protein and both isoforms of the MEN2B-Ret protein bound preferentially to the Shc PTB domain. On the other hand, the short isoform of MEN2A-Ret bound to the PTB and SH2 domains. In neuroblastoma cells expressing both isoforms of Ret, its activation by GDNF also resulted in the binding of both domains. GDNF and MEN 2A mutations activate Ret by inducing its dimerization, whereas the MEN 2B mutation increases Ret catalytic activity without dimerization. Our results thus suggest that Ret dimerization might be required for binding of the Shc SH2 domain to the short isoform.
AB - We analyzed the intracellular signalling pathway through Ret activated by glial-cell-line-derived neurotrophic factor (GDNF), multiple endocrine neoplasia (MEN) 2A and 2B mutations. The results showed that all of them induce a signal transducing complex consisting of Ret, Shc, and Grb2 proteins. In addition, GDNF clearly activated a Ras-MAPK pathway in human neuroblastoma cells. Ret is expressed mainly as two isoforms that differ in the carboxy-terminal sequence: a long isoform (1114 amino acids) and a short isoform (1072 amino acids). The long isoform contains the consensus sequence for binding of the Shc PTB domain but not of its SH2 domain, whereas the short isoform has the consensus sequences for binding of both domains. In vitro binding assay revealed that the long isoform of the MEN2A-Ret protein and both isoforms of the MEN2B-Ret protein bound preferentially to the Shc PTB domain. On the other hand, the short isoform of MEN2A-Ret bound to the PTB and SH2 domains. In neuroblastoma cells expressing both isoforms of Ret, its activation by GDNF also resulted in the binding of both domains. GDNF and MEN 2A mutations activate Ret by inducing its dimerization, whereas the MEN 2B mutation increases Ret catalytic activity without dimerization. Our results thus suggest that Ret dimerization might be required for binding of the Shc SH2 domain to the short isoform.
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U2 - 10.1006/bbrc.1997.7225
DO - 10.1006/bbrc.1997.7225
M3 - Article
C2 - 9299438
AN - SCOPUS:0031589554
SN - 0006-291X
VL - 237
SP - 747
EP - 751
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 3
ER -