ApoE4 Recombinant Rabbit mAb (SDT-1849-68)

Apolipoprotein E (ApoE) is a multifunctional protein that plays a crucial role in lipid metabolism and transport. It is synthesized primarily in the liver and brain, and it helps in the formation and clearance of chylomicrons and very low-density lipoproteins (VLDLs), which are essential for the transport of dietary lipids and endogenous lipids throughout the body. ApoE exists in three major isoforms—ApoE2, ApoE3, and ApoE4—each with distinct genetic and functional characteristics. ApoE3 is considered the most common and neutral form, while ApoE4 is associated with an increased risk of developing late-onset Alzheimer's disease and cardiovascular diseases due to its role in promoting amyloid-beta aggregation and impaired lipid clearance. The earliest identified and most significantly associated genetic risk factor for AD is the E4 allele of the APOE, which markedly increases AD risk relative to the APOE3 allele, while the APOE2 allele is considered protective. A single amino acid difference between APOE3 (Cys112) and APOE4 (Arg112) results in a protein conformational change that affects binding to apolipoprotein receptors, lipids, and Aβ. Brain APOE is mainly produced by astrocytes and secreted to the extracellular space, where it serves as the primary cholesterol carrier. Importantly, APOE is expressed by other brain cell types including neurons and microglia, where its expression can be altered under neuropathological conditions.