Apolipoprotein E

Title: Apolipoprotein E
Additional Names: ApoE
Literature References: Protein component of several classes of lipoproteins; plays a central role in plasma lipoprotein metabolism and cholesterol transport. Also involved in lipid-transport in the development and repair of nervous tissue. Polymorphic glycoprotein containing 299 amino acid residues; mol wt 34.2 kDa. Three major isoforms have been identified in humans (apo-E2, E3, E4) which are the product of 3 independent alleles (e2, e3, e4) at a single gene locus. The isoforms differ from each other only in cysteine-arginine interchanges at 2 substitution sites. Allele e3 is the most common; inheritance of e4 has been associated with increased risk of Alzheimer's disease. Primarily synthesized in the liver by parenchymal cells and in the brain by astrocytes. Also produced in significant amounts by mature macrophages. Discovery as component of VLDL: V. G. Shore, B. Shore, Biochemistry 12, 502 (1973). Purification and characterization: V. I. Zannis, J. L. Breslow, Mol. Cell. Biochem. 42, 3 (1982). Amino acid sequence: S. C. Rall, Jr. et al., J. Biol. Chem. 257, 4171 (1982). Biosynthesis and activity: R. W. Mahley, Science 240, 622 (1988). Association with Alzheimer's disease: A. M. Saunders et al., Neurology 43, 1467 (1993); L. A. Farrer et al., J. Am. Med. Assoc. 278, 1349 (1997). Review of role in lipoprotein metabolism: A. D. Dergunov, M. Rosseneu, Biol. Chem. Hoppe-Seyler 375, 485-495 (1994); P. de Knijff et al., Hum. Mutat. 4, 178-194 (1994). Review of role in the nervous system: J. Poirier, Trends Neurosci. 17, 525-530 (1994); K. H. Weisgraber et al., Curr. Opin. Lipidol. 5, 110-116 (1994); R. W. Mahley et al., ibid. 6, 86-91 (1995).
Apoptolidin Aporeine Appetize? Apraclonidine Apramycin

Apolipoprotein E

PDB rendering based on 1b68.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols APOE (; AD2; LDLCQ5; LPG)
External IDs OMIM: 107741 MGI: 88057 HomoloGene: 30951 GeneCards: APOE Gene
RNA expression pattern
PBB GE APOE 203382 s at tn.png
PBB GE APOE 203381 s at.png
PBB GE APOE 212884 x at.png
More reference expression data
Orthologs
Species Human Mouse
Entrez 348 11816
Ensembl ENSG00000130203 ENSMUSG00000002985
UniProt P02649 P08226
RefSeq (mRNA) NM_000041 NM_009696
RefSeq (protein) NP_000032 NP_033826
Location (UCSC) Chr 19:
45.41 – 45.41 Mb
Chr 7:
19.7 – 19.7 Mb
PubMed search [1] [2]

Apolipoprotein E (ApoE) is a class of apolipoprotein found in the chylomicron and Intermediate-density lipoprotein (IDLs) that is essential for the normal catabolism of triglyceride-rich lipoprotein constituents.[1] In peripheral tissues, ApoE is primarily produced by the liver and macrophages, and mediates cholesterol metabolism in an isoform-dependent manner. In the central nervous system, ApoE is mainly produced by astrocytes, and transports cholesterol to neurons via ApoE receptors, which are members of the low density lipoprotein receptor gene family.