A mechanistic basis for converting a receptor tyrosine kinase agonist to an antagonist

doi:10.1073/pnas.0704290104

A mechanistic basis for converting a receptor tyrosine kinase agonist to an antagonist

*Laboratory of Structural Sciences,
^†Laboratory of Molecular Oncology, and
^‡Laboratory of Integrin Signaling and Tumorigenesis, Van Andel Research Institute, 333 Bostwick Avenue, Grand Rapids, MI 49503; and
^§Medical Research Council Centre, Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom

Edited by Joseph Schlessinger, Yale University School of Medicine, New Haven, CT, and approved July 25, 2007 (received for review May 8, 2007)

Abstract

Hepatocyte growth factor (HGF) activates the Met receptor tyrosine kinase by binding and promoting receptor dimerization. Here we describe a mechanistic basis for designing Met antagonists based on NK1, a natural variant of HGF containing the N-terminal and the first kringle domain. Through detailed biochemical and structural analyses, we demonstrate that both mouse and human NK1 induce Met dimerization via a conserved NK1 dimer interface. Mutations designed to alter the NK1 dimer interface abolish its ability to promote Met dimerization but retain full Met-binding activity. Importantly, these NK1 mutants act as Met antagonists by inhibiting HGF-mediated cell scattering, proliferation, branching, and invasion. The ability to separate the Met-binding activity of NK1 from its Met dimerization activity thus provides a rational basis for designing Met antagonists. This strategy of antagonist design may be applicable for other growth factor receptors by selectively abolishing the receptor activation ability but not the receptor binding of the growth factors.

Footnotes

^¶To whom correspondence may be addressed. E-mail: egherard{at}mrc-lmb.cam.ac.uk or eric.xu{at}vai.org
Author contributions: G.V.W. and H.E.X. designed research; W.D.T., J.D., C.G., Q.X., and C.M. performed research; E.G. and G.V.W. contributed new reagents/analytic tools; W.D.T., J.D., C.G., C.M., G.V.W., and H.E.X. analyzed data; and W.D.T., J.D., C.G., C.M., E.G., G.V.W., and H.E.X. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
Data deposition: The atomic coordinates and structure factors have been deposited in the Protein Data Bank, www.pdb.org (PDB ID codes 2QJ4 and 2QJ2).
This article contains supporting information online at www.pnas.org/cgi/content/full/0704290104/DC1.
Abbreviations:

HGF,

hepatocyte growth factor;

RTK,

receptor tyrosine kinase;

uPA,

urokinase-type plasminogen activator;

MDCK,

Madin–Darby canine kidney;

NGF,

nerve growth factor.
Freely available online through the PNAS open access option.