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Characterization of alpha 2-macroglobulin binding to human trabecular meshwork cells: presence of the alpha 2-macroglobulin signaling receptor.

Publication ,  Journal Article
Howard, GC; Roberts, BC; Epstein, DL; Pizzo, SV
Published in: Arch Biochem Biophys
September 1, 1996

Direct binding of receptor-recognized alpha 2-macroglobulin (alpha 2M*) or a cloned receptor binding fragment from rat alpha 1-macroglobulin (RBF) to human trabecular meshwork cells demonstrated two classes of cell surface binding sites. One class has an apparent Kd of 5.0 nM and a receptor number of 31,800 receptors/cell. The other class has an apparent Kd of 20 pM and a receptor number of 1600 receptors/cell. Binding studies of alpha 2M* or RBF in the presence of a competitor for binding to low-density-lipoprotein receptor-related protein/alpha 2M* receptor (LRP/alpha 2MR) called receptor-associated protein (RAP) show that only the lower affinity class of binding sites is susceptible to competition with RAP. Uptake studies demonstrate specific internalization and degradation of alpha 2M* which is inhibitable by RAP. Exposure of the cells to alpha 2M* and RBF (40 nM) is associated with mean increases of 171 and 210%, respectively, in the intracellular calcium concentration, which is not inhibitable by RAP or pertussis toxin. These studies present the first characterization of alpha 2M* and RBF signaling in a primary human cell type and suggest a role for alpha 2M* in the physiology of the eye.

Duke Scholars

Published In

Arch Biochem Biophys

DOI

ISSN

0003-9861

Publication Date

September 1, 1996

Volume

333

Issue

1

Start / End Page

19 / 26

Location

United States

Related Subject Headings

  • alpha-Macroglobulins
  • Trabecular Meshwork
  • Recombinant Proteins
  • Receptors, LDL
  • Receptors, Immunologic
  • Rats
  • Peptide Fragments
  • Molecular Sequence Data
  • Membrane Glycoproteins
  • Low Density Lipoprotein Receptor-Related Protein-1
 

Citation

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MLA
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Howard, G. C., Roberts, B. C., Epstein, D. L., & Pizzo, S. V. (1996). Characterization of alpha 2-macroglobulin binding to human trabecular meshwork cells: presence of the alpha 2-macroglobulin signaling receptor. Arch Biochem Biophys, 333(1), 19–26. https://doi.org/10.1006/abbi.1996.0359
Howard, G. C., B. C. Roberts, D. L. Epstein, and S. V. Pizzo. “Characterization of alpha 2-macroglobulin binding to human trabecular meshwork cells: presence of the alpha 2-macroglobulin signaling receptor.Arch Biochem Biophys 333, no. 1 (September 1, 1996): 19–26. https://doi.org/10.1006/abbi.1996.0359.
Howard, G. C., et al. “Characterization of alpha 2-macroglobulin binding to human trabecular meshwork cells: presence of the alpha 2-macroglobulin signaling receptor.Arch Biochem Biophys, vol. 333, no. 1, Sept. 1996, pp. 19–26. Pubmed, doi:10.1006/abbi.1996.0359.
Journal cover image

Published In

Arch Biochem Biophys

DOI

ISSN

0003-9861

Publication Date

September 1, 1996

Volume

333

Issue

1

Start / End Page

19 / 26

Location

United States

Related Subject Headings

  • alpha-Macroglobulins
  • Trabecular Meshwork
  • Recombinant Proteins
  • Receptors, LDL
  • Receptors, Immunologic
  • Rats
  • Peptide Fragments
  • Molecular Sequence Data
  • Membrane Glycoproteins
  • Low Density Lipoprotein Receptor-Related Protein-1