Specific Uncoupling of GRB2 from the Met Receptor

doi:10.1074/jbc.271.24.14119

Specific Uncoupling of GRB2 from the Met Receptor

DIFFERENTIAL EFFECTS ON TRANSFORMATION AND MOTILITY*

From the ^‡ Department of Biomedical Sciences and Human Oncology, Università di Torino, 10126 Torino, Italy and
^” Ludwig Institute for Cancer Research, London W1P 8BT, United Kingdom

^§ To whom correspondence should be addressed:
Dept. of Biomedical Sciences, Università di Torino, C.so Massimo d'Azeglio 52, 10126, Torino, Italy.
Tel.: 39-11-6707799; Fax: 39-11-6509105; E-mail: Ponzetto{at}morgagni.biomed.unito.it

↵^¶ Present address: Chiron Corporation, Emeryville, CA 94608.
↵^‴ Present address: Division of Cell and Molecular Biology, Dana Farber Cancer Institute, Boston, MA 02115.

Abstract

The biological effects of hepatocyte growth factor/scatter factor are mediated by autophosphorylation of its receptor, the Met tyrosine kinase, on two carboxyl-terminal tyrosines. These phosphotyrosines (Y¹³⁴⁹VHVNATY¹³⁵⁶VNV) are multifunctional docking sites for several effectors. Grb2, the adaptor for the Ras guanyl-nucleotide exchanger SOS, binds to Tyr¹³⁵⁶ in the YVV motif. By site-directed mutagenesis we either abrogated or duplicated the Grb2 consensus, without interfering with the other effectors. Loss of the link with Grb2 severely impaired transformation. The same mutation, however, had no effect on the “scattering” response, indicating that the level of signal which can be reached by Grb2-independent routes is permissive for motility. Duplication of the Grb2 binding site enhanced transformation and left motility unchanged. Thus, two Met-mediated biological responses, motility and growth, can be dissociated on the basis of their differential requirement for a direct link with Ras.

Footnotes

↵^∥ Supported by an Associazione Italiana delle Ricerche sul Cancro (AIRC) Fellowship.
↵* This work was supported by grants from the Associazione Italiana delle Ricerche sul Cancro (AIRC), from the Consiglio Nazionale delle Ricerche (CNR: Special Project ACRO, Grant 92.02169.PF39). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

HGF/SF

hepatocyte growth factor/scatter factor

SH2

src homology region 2

SOS

son of sevenless

MDCK cells

Madin-Darby canine kidney cells

NGF

nerve growth factor

DMEM

Dulbecco's modified Eagle's medium

FCS

fetal calf serum

GST

gluthatione S-transferase

PAGE

polyacrylamide gel electrophoresis

MAP

mitogen-activated protein

MET, TPR-MET, TRK

human cDNA

Met, Tpr-Met, Trk

protein product.
↵² D. Besser, A. Bardelli, S. Didichenko, M. Thelen, P. M. Comoglio, C. Ponzetto, and Y. Nagamine, manuscript submitted for publication.
- Received December 13, 1995.
- Revision received March 25, 1996.