PMID: 9643348Jun 27, 1998Paper

The carboxyl terminus in apolipoprotein E2 and the seven amino acid repeat in apolipoprotein E-Leiden: role in receptor-binding activity.

Journal of Lipid Research
L M DongK H Weisgraber

Abstract

Both apolipoprotein (apo) E2 and apoE-Leiden (tandem repeat of amino acids 121-127) are associated with type III hyperlipoproteinemia and bind defectively to low density lipoprotein receptors. Removing the carboxyl terminus of both variants (residues 192-299) increases receptor-binding activity, suggesting that the carboxyl terminus modulates activity. To identify the region(s) that modulated binding activity, we produced carboxyl-terminal truncations in apoE2 and apoE-Leiden (terminating at positions 191, 223, 244, and 272) and in apoE3 (terminating at positions 191, 223, and 244) and compared their receptor-binding activities as dimyristoylphosphatidylcholine (DMPC) discs. The results suggest that the entire carboxyl terminus up to residue 272, not a discrete smaller segment, is responsible for the modulation in apoE2. Intact apoE-Leiden and the 223 and 244 variants displayed similar activities (approximately 25% of apoE3's), but the 191 variant's activity was identical to that of intact apoE3. ApoE-Leiden and its truncated variants formed larger DMPC discs than did intact or truncated apoE3 or apoE2. These discs contained more apoE molecules than apoE3 discs, suggesting that the apparently normal binding activity of the apoE...Continue Reading

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.

ApoE Phenotypes

Apolipoprotein E (APOE) is a protein involved in fat metabolism and associated with the pathogenesis of Alzheimer's disease and cardiovascular disease. Here is the latest research on APOE phenotypes.