Thromb Haemost 2002; 87(05): 880-887
DOI: 10.1055/s-0037-1613100
Review Article
Schattauer GmbH

Platelet Activation by the apoB/E Receptor-binding Domain of LDL

I. A. M. Relou
1   Laboratory for Thrombosis and Haemostasis, Department of Haematology, University of Utrecht, The Netherlands
,
G. Gorter
1   Laboratory for Thrombosis and Haemostasis, Department of Haematology, University of Utrecht, The Netherlands
,
J. M. H. van Rijn
2   Department of Clinical Chemistry, University Medical Center Utrecht, and Institute for Biomembranes, University of Utrecht, The Netherlands
,
N. J.-W. Akkerman
1   Laboratory for Thrombosis and Haemostasis, Department of Haematology, University of Utrecht, The Netherlands
› Author Affiliations
Further Information

Publication History

Received 20 August 2001

Accepted after revision 01 February 2002

Publication Date:
11 December 2017 (online)

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Summary

Low density lipoprotein (LDL) increases the sensitivity of human platelets for agonists by activating p38MAPK. Antibody 4G3 disturbs apoB100 binding to the classical apoB/E receptor and inhibits LDLinduced p38MAPK activation, whereas an antibody against a distal domain on apoB100 has no effect. Peptide RLTRKRGLKLA mimics the binding domain of apoB100 called the B-site and activates platelet p38MAPK. Activation by B-site peptide is dose-dependent, transient and followed by desensitization, in accordance with receptor-mediated signalling. A scrambled peptide and a partially homologous peptide RKLRKRLLRDA mimicking the apoB/E receptor binding site of apoE in high density lipoprotein (HDL) also activate p38MAPK albeit 40% weaker, but an uncharged peptide lacks p38MAPK activating capacity. LDL and B-site peptide bind to the same binding sites and initiate similar signalling to p38MAPK and cytosolic phospholipase A2. Thus, LDL and to a lesser extent HDL activate platelets via specific domains in the protein moiety that recognize receptors of the LDL receptor family.