The adhesion of cells to collagen is of fundamental significance to many of the key events in normal and pathologic biology including primary hemostasis. This process can be initiated by the adhesion and subsequent activation of platelets by exposed subendothelial collagen. The experiments outlined in this proposal are directed toward delineating at the cellular and molecular level the mechanisms by which platelets and possibly other cell types interact directly with collagen. I will characterize and unambiguously establish the role in platelet-collagen adhesion of a 160/130 kDa, Mg++-dependent collagen binding protein recently isolated from platelet membranes in my laboratory. This protein complex is the likely mediator of a Mg++-dependent mechanism of platelet-collagen adhesion recently shown by my laboratory to support a rate and extent of adhesion far greater than the more frequently studied divalent cation-independent mechanism. The relationship between the Mg++-dependent and divalent cation- independent mechanisms of adhesion will be established by the combined use of biochemical and immunochemical approaches. The association of the 160/130 kDa collagen binding protein with the platelet cytoskeleton will be established. I will also examine the participation of the 160/130 kDa complex in ligand induced clustering on the platelet surface as previously proposed in our model for the role of multiple, simultaneous, and linked interactions in platelet-collagen adhesion. Finally, I will establish the presence and function of proteins immunochemically related to the platelet surface collagen binding complex on the surfaces of other cell types. Our very recent observation that the platelet surface collagen binding complex is specifically immunoprecipitated by the monoclonal antibody 12F1 which defines the alpha subunit of the VLA-2 antigen which is present on other cells lends further credence to the hypothesis that other cell types adhere to collagen by mechanisms similar or identical to that employed by platelets.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL040506-01
Application #
3357707
Study Section
Hematology Subcommittee 2 (HEM)
Project Start
1988-04-01
Project End
1993-03-31
Budget Start
1988-04-01
Budget End
1989-03-31
Support Year
1
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Washington University
Department
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Dickeson, S K; Mathis, N L; Rahman, M et al. (1999) Determinants of ligand binding specificity of the alpha(1)beta(1) and alpha(2)beta(1) integrins. J Biol Chem 274:32182-91
Zutter, M M; Santoro, S A; Wu, J E et al. (1999) Collagen receptor control of epithelial morphogenesis and cell cycle progression. Am J Pathol 155:927-40
Bhattacharyya-Pakrasi, M; Dickeson, S K; Santoro, S A (1998) Alpha2beta1 integrin recognition of the carboxyl-terminal propeptide of type I procollagen: integrin recognition and feed-back regulation of matrix biosynthesis are mediated by distinct sequences. Matrix Biol 17:223-32
Dickeson, S K; Bhattacharyya-Pakrasi, M; Mathis, N L et al. (1998) Ligand binding results in divalent cation displacement from the alpha 2 beta 1 integrin I domain: evidence from terbium luminescence spectroscopy. Biochemistry 37:11280-8
Staatz, W D; Walsh, J J; Santoro, S A (1997) The alpha 2 beta 1 integrin binds to the CB4 peptide of the alpha 2(I) collagen chain. Biochem Mol Biol Int 42:577-82
Dickeson, S K; Walsh, J J; Santoro, S A (1997) Contributions of the I and EF hand domains to the divalent cation-dependent collagen binding activity of the alpha2beta1 integrin. J Biol Chem 272:7661-8
Wu, J E; Santoro, S A (1996) Differential expression of integrin alpha subunits supports distinct roles during lung branching morphogenesis. Dev Dyn 206:169-81
Zutter, M M; Fong, A M; Krigman, H R et al. (1992) Differential regulation of the alpha 2 beta 1 and alpha IIb beta 3 integrin genes during megakaryocytic differentiation of pluripotential K562 cells. J Biol Chem 267:20233-8
Burger, S R; Zutter, M M; Sturgill-Koszycki, S et al. (1992) Induced cell surface expression of functional alpha 2 beta 1 integrin during megakaryocytic differentiation of K562 leukemic cells. Exp Cell Res 202:28-35
Staatz, W D; Fok, K F; Zutter, M M et al. (1991) Identification of a tetrapeptide recognition sequence for the alpha 2 beta 1 integrin in collagen. J Biol Chem 266:7363-7

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