Abstract

The objective of this research program is to characterize the role of the proteinase inhibitor alpha2-macroglobulin (alpha2M) and the alpha2M receptor in the regulation of cellular growth. Alpha2M inhibits proteinases from all four major classes; however, the function of alpha2M remains unclear. Recent studies have demonstrated that alpha2M binds many cytokines including transforming growth factor-beta1 (TGF-beta1), TGF- beta2, interleukin-1beta and tumor necrosis factor-alpha. After reaction with proteinase, alpha2M undergoes conformational change and expresses altered cytokine binding affinity. Work from this laboratory demonstrated that the alpha2M receptor mediates cellular uptake of alpha2M-TGF-beta1 complexes. The significance of this process is unknown.
The first aim of this proposal is to study the formation and activity of alpha2M-cytokine complexes. Purified alpha2M-proteinase complexes and structurally modified alpha2M variants will be used to analyze the role of alpha2M conformation in cytokine binding. Anti-alpha2M monoclonal antibodies will also be applied in this analysis. Model systems (in vitro and in vivo) will be developed to determine the significance of alpha2M-cytokine interactions. Does alpha2M serve to clear cytokines from the plasma and related fluids or is alpha2M a carrier that targets active signalling molecules to specific cells? Experiments using cell culture and animal model systems will address this question and provide information regarding the role of alpha2M in biological processes such as hematopoiesis and neoplasia. The cytokine carrier activity of other proteins including thrombospondin will be evaluated.
A final aim will be to characterize the modulation of alpha2M receptor expression by cytokines including some that bind to alpha2M. Receptor expression will be determined using 125I-alpha2M-methylamine binding studies, a specific anti-alpha2M receptor monoclonal antibody, and a cDNA probe that hybridizes with murine or human alpha2M receptor mRNA. The goal of this program is to advance our understanding of the function of alpha2M and the alpha2M receptor in cellular growth, differentiation and neoplastic transformation. Ultimately, these studies will provide information regarding growth factor-carrier interactions in general.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA053462-02
Application #
3198167
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1992-08-01
Project End
1996-07-31
Budget Start
1993-08-01
Budget End
1994-07-31
Support Year
2
Fiscal Year
1993
Total Cost
Indirect Cost

  Institution

Name
University of Virginia
Department
Type
Schools of Medicine
DUNS #
001910777
City
Charlottesville
State
VA
Country
United States
Zip Code
22904

  Publications

Arandjelovic, Sanja; Dragojlovic, Nikola; Li, Xiaoqing et al. (2007) A derivative of the plasma protease inhibitor alpha(2)-macroglobulin regulates the response to peripheral nerve injury. J Neurochem 103:694-705
Arandjelovic, Sanja; Van Sant, Cristina L; Gonias, Steven L (2006) Limited mutations in full-length tetrameric human alpha2-macroglobulin abrogate binding of platelet-derived growth factor-BB and transforming growth factor-beta1. J Biol Chem 281:17061-8
Mettenburg, Joseph M; Gonias, Steven L (2005) Beta-amyloid peptide binds equivalently to binary and ternary alpha2-macroglobulin-protease complexes. Protein J 24:89-93
Mettenburg, Joseph M; Arandjelovic, Sanja; Gonias, Steven L (2005) A chemically modified preparation of alpha2-macroglobulin binds beta-amyloid peptide with increased affinity and inhibits Abeta cytotoxicity. J Neurochem 93:53-62
Arandjelovic, Sanja; Hall, Brian D; Gonias, Steven L (2005) Mutation of lysine 1370 in full-length human alpha2-macroglobulin blocks binding to the low density lipoprotein receptor-related protein-1. Arch Biochem Biophys 438:29-35
Gonias, Steven L; Wu, Lihua; Salicioni, Ana Maria (2004) Low density lipoprotein receptor-related protein: regulation of the plasma membrane proteome. Thromb Haemost 91:1056-64
Arandjelovic, Sanja; Freed, Tiffany A; Gonias, Steven L (2003) Growth factor-binding sequence in human alpha2-macroglobulin targets the receptor-binding site in transforming growth factor-beta. Biochemistry 42:6121-7
Hope, Caroline; Mettenburg, Joseph; Gonias, Steven L et al. (2003) Functional analysis of plasma alpha(2)-macroglobulin from Alzheimer's disease patients with the A2M intronic deletion. Neurobiol Dis 14:504-12
Mathew, Smitha; Arandjelovic, Sanja; Beyer, Wayne F et al. (2003) Characterization of the interaction between alpha2-macroglobulin and fibroblast growth factor-2: the role of hydrophobic interactions. Biochem J 374:123-9
Mettenburg, Joseph M; Webb, Donna J; Gonias, Steven L (2002) Distinct binding sites in the structure of alpha 2-macroglobulin mediate the interaction with beta-amyloid peptide and growth factors. J Biol Chem 277:13338-45

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