The relationship between low density lipoprotein-related protein/alpha 2-macroglobulin (alpha 2M) receptors and the newly described alpha 2M signaling receptor.

Journal Article (Journal Article)

alpha 2-Macroglobulin (alpha 2M)-methylamine binding to macrophages appears to involve two receptors. Binding of alpha 2M-methylamine to low density lipoprotein-related protein (LRP) results in cellular uptake and degradation, while binding to a newly described alpha 2M signaling receptor elevates intracellular calcium ([Ca2+]i) and inositol phosphates. We now demonstrate that binding of lactoferrin, Pseudomonas exotoxin A, and lipoprotein lipase to LRP on macrophages results in increased [Ca2+]i and inositol 1,4,5-triphosphate. Receptor-associated protein, which binds to LRP but not the alpha 2M signaling receptor, blocks the lactoferrin signal but has no effect on alpha 2M-methylamine signaling. The latter observation supports our hypothesis that a distinct signaling receptor binds alpha 2M-methylamine. We further demonstrate that the signaling events induced by lactoferrin may involve a pertussis toxin-sensitive G protein, while the alpha 2M signaling receptor appears to be coupled to a pertussis toxin-insensitive G protein.

Full Text

Duke Authors

Cited Authors

  • Misra, UK; Chu, CT; Gawdi, G; Pizzo, SV

Published Date

  • July 15, 1994

Published In

Volume / Issue

  • 269 / 28

Start / End Page

  • 18303 - 18306

PubMed ID

  • 7518427

Pubmed Central ID

  • 7518427

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States