apolipoprotein E(redirected from Apo E)
an apolipoprotein found in several plasma lipoprotein particles including chylomicrons, VLDL, and HDL. Three major isoforms are encoded by three common alleles at the Apo E locus: E2, E2, and E4. The E2 allele is associated with lower total plasma cholesterol and LDL cholesterol than is E3, whereas E4 is associated with higher LDL and total cholesterol than E3.
APOEA gene on chromosome 19q13.2 that encodes apolipoprotein E, the main apoprotein of chylomicrons, which binds to a specific receptor on liver cells and peripheral cells. ApoE mediates binding, internalisation and catabolism of lipoprotein particles and serves as a ligand for the LDL (apo B/E) receptor.
APOE mutations cause hyperlipoproteinaemia type III (familial dysbetalipoproteinaemia), which is characterised by increased plasma cholesterol and triglycerides due to impaired chylomicron and VLDL remnant clearance.