Basic fibroblast growth factor (FGF-2) is important in development, wound healing and angiogenesis. The human plasma proteinase inhibitor α2-macroglobulin (α2M) binds to and regulates the biological activity of various growth factors, including FGF-2. FGF-2 binds specifically and saturably to native α2M and conformationally modified α2M (α2M∗); however, the KD for FGF-2 binding to α2M∗ is 10-fold lower. This study investigates the biochemical nature of the interaction between FGF-2 and α2M∗ and localizes a possible FGF-2 binding site in the α2M subunit. FGF-2 binding to α2M∗ was not affected by shifts in pH between 6.5 and 10; however, increasing temperature decreased the KD for this interaction. The binding affinity of FGF-2 for α2M∗ also increased with increasing ionic strength. These results are consistent with the hypothesis that hydrophobic interactions predominate in promoting FGF-2 association with α2M∗. Consistent with this hypothesis, FGF-2 bound to a glutathione S-transferase fusion protein containing amino acids 591–774 of the α2M subunit (FP3) and to a hydrophobic 16-amino-acid peptide (amino acids 718–733) within FP3. Specific binding of FGF-2 to the 16-amino-acid peptide was inhibited by excess transforming growth factor-β1. When the 16-amino-acid peptide was chemically modified to neutralize the only two charged amino acids, FGF-2-binding activity was unaffected, supporting the predominant role of hydrophobic interactions. FGF-2 presentation to signalling receptors is influenced by growth factor binding to heparan sulphate proteoglycans (HSPGs), which is electrostatic in nature. Our results demonstrate that the interactions of FGF-2 with α2M∗ and HSPGs are biochemically distinct, suggesting that different FGF-2 sequences are involved.
Skip Nav Destination
Article navigation
August 2003
- PDF Icon PDF LinkFront Matter
Research Article|
August 15 2003
Characterization of the interaction between α2-macroglobulin and fibroblast growth factor-2: the role of hydrophobic interactions
Smitha MATHEW;
Smitha MATHEW
∗Department of Pathology, Box 3712, Duke University Medical Center, Durham, NC 27710, U.S.A.
Search for other works by this author on:
Sanja ARANDJELOVIC;
Sanja ARANDJELOVIC
†Departments of Pathology, Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, U.S.A.
Search for other works by this author on:
Wayne F. BEYER;
Wayne F. BEYER
∗Department of Pathology, Box 3712, Duke University Medical Center, Durham, NC 27710, U.S.A.
Search for other works by this author on:
Steven L. GONIAS;
Steven L. GONIAS
†Departments of Pathology, Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, U.S.A.
Search for other works by this author on:
Salvatore V. PIZZO
Salvatore V. PIZZO
1
∗Department of Pathology, Box 3712, Duke University Medical Center, Durham, NC 27710, U.S.A.
1To whom correspondence should be addressed (e-mail pizzo001@mc.duke.edu).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
October 22 2002
Revision Received:
March 31 2003
Accepted:
May 19 2003
Accepted Manuscript online:
May 19 2003
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2003
2003
Biochem J (2003) 374 (1): 123–129.
Article history
Received:
October 22 2002
Revision Received:
March 31 2003
Accepted:
May 19 2003
Accepted Manuscript online:
May 19 2003
Citation
Smitha MATHEW, Sanja ARANDJELOVIC, Wayne F. BEYER, Steven L. GONIAS, Salvatore V. PIZZO; Characterization of the interaction between α2-macroglobulin and fibroblast growth factor-2: the role of hydrophobic interactions. Biochem J 15 August 2003; 374 (1): 123–129. doi: https://doi.org/10.1042/bj20021655
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.