BACKGROUND: Although a number of growth factors bind cell-surface heparan sulphate proteoglycans (HSPGs), the role of this interaction is unclear except for fibroblast growth factor which requires HSPG binding for signalling. Hepatocyte growth factor/scatter factor (HGF/SF) plays important roles in mammalian development and tissue regeneration and acts on target cells through a specific receptor tyrosine kinase encoded by the c-met proto-oncogene. This factor also binds HSPGs with high affinity, but conflicting data have been reported on the role of HSPG binding in HGF/SF signalling. RESULTS: To map the binding sites for HSPG and the Met receptor in HGF/SF, we have engineered a number of HGF/SF mutants in which several clusters of solvent-accessible residues in the hairpin structure of the amino-terminal domain or in kringle 2 have been replaced. Two of the mutants (HP1 and HP2) showed greatly decreased (more than 50-fold) affinity for heparin and HSPGs but retained full mitogenic and motogenic activities on target cells in culture. Furthermore, when compared with wild-type HGF/SF, the HP1 mutant exhibited a delayed clearance from the blood, higher tissue levels and a higher induction of DNA synthesis in normal, adult murine liver. CONCLUSIONS: These results establish the following: the binding sites in HGF/SF for Met and for HSPGs can be dissociated by protein engineering; high-affinity binding of HGF/SF to HSPGs is not essential for signalling; one role of HSPG binding in the HGF/SF system appears to be sequestration and degradation of the growth factor; and HGF/SF mutants with decreased affinity for HSPGs exhibit enhanced activity in vivo.
BACKGROUND: Although a number of growth factors bind cell-surface heparan sulphate proteoglycans (HSPGs), the role of this interaction is unclear except for fibroblast growth factor which requires HSPG binding for signalling. Hepatocyte growth factor/scatter factor (HGF/SF) plays important roles in mammalian development and tissue regeneration and acts on target cells through a specific receptor tyrosine kinase encoded by the c-met proto-oncogene. This factor also binds HSPGs with high affinity, but conflicting data have been reported on the role of HSPG binding in HGF/SF signalling. RESULTS: To map the binding sites for HSPG and the Met receptor in HGF/SF, we have engineered a number of HGF/SF mutants in which several clusters of solvent-accessible residues in the hairpin structure of the amino-terminal domain or in kringle 2 have been replaced. Two of the mutants (HP1 and HP2) showed greatly decreased (more than 50-fold) affinity for heparin and HSPGs but retained full mitogenic and motogenic activities on target cells in culture. Furthermore, when compared with wild-type HGF/SF, the HP1 mutant exhibited a delayed clearance from the blood, higher tissue levels and a higher induction of DNA synthesis in normal, adult murine liver. CONCLUSIONS: These results establish the following: the binding sites in HGF/SF for Met and for HSPGs can be dissociated by protein engineering; high-affinity binding of HGF/SF to HSPGs is not essential for signalling; one role of HSPG binding in the HGF/SF system appears to be sequestration and degradation of the growth factor; and HGF/SF mutants with decreased affinity for HSPGs exhibit enhanced activity in vivo.
Authors: Véronique Orian-Rousseau; Linfeng Chen; Jonathan P Sleeman; Peter Herrlich; Helmut Ponta Journal: Genes Dev Date: 2002-12-01 Impact factor: 11.361
Authors: Cassie J Liu; Douglas S Jones; Ping-Chuan Tsai; Abhishek Venkataramana; Jennifer R Cochran Journal: FEBS Lett Date: 2014-11-21 Impact factor: 4.124
Authors: Thivyan Thayaparan; Roseanna M Petrovic; Daniela Y Achkova; Tomasz Zabinski; David M Davies; Astero Klampatsa; Ana C Parente-Pereira; Lynsey M Whilding; Sjoukje Jc van der Stegen; Natalie Woodman; Michael Sheaff; Jennifer R Cochran; James F Spicer; John Maher Journal: Oncoimmunology Date: 2017-08-14 Impact factor: 8.110
Authors: Malgorzata Borowiak; Alistair N Garratt; Torsten Wüstefeld; Michael Strehle; Christian Trautwein; Carmen Birchmeier Journal: Proc Natl Acad Sci U S A Date: 2004-07-12 Impact factor: 11.205