Recombinant Human APOE Protein, His-tagged

• Cat.No.: APOE-17H
• Product Overview: Recombinant human APOE protein with a His-tag was expressed in HEK293

Specification

• Species: Human
• Source: HEK293
• Tag: His
• Description: The protein encoded by this gene is a major apoprotein of the chylomicron. It binds to a specific liver and peripheral cell receptor, and is essential for the normal catabolism of triglyceride-rich lipoprotein constituents. This gene maps to chromosome 19 in a cluster with the related apolipoprotein C1 and C2 genes. Mutations in this gene result in familial dysbetalipoproteinemia, or type III hyperlipoproteinemia (HLP III), in which increased plasma cholesterol and triglycerides are the consequence of impaired clearance of chylomicron and VLDL remnants.
• Molecular Mass: The protein has a calculated MW of 35 kDa.
• AA Sequence: KVEQAVETEPEPELRQQTEWQSGQRWELALGRFWDYLRWVQTLSEQVQEELLSSQVTQELRALMDETMKELKAYKSELEEQLTPVAEETRARLSKELQAAQARLGADMEDVCGRLVQYRGEVQAMLGQSTEELRVRLASHLRKLRKRLLRDADDLQKRLAVYQAGAREGAERGLSAIRERLGPLVEQGRVRAATVGSLAGQPLQERAQAWGERLRARMEEMGSRTRDRLDEVKEQVAEVRAKLEEQAQQIRLQAEAFQARLKSWFEPLVEDMQRQWAGLVEKVQAAVGTSAAPVPSDNHVDHHHHHH
• Endotoxin: <1 EU/μg
• Purity: >95% by SDS-PAGE
• Storage: Store it under sterile conditions at -20 to -80 centigrade. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.
• Storage Buffer: Lyophilized from a 0.2 μm filtered solution of PBS,pH7.4, 5% trehalose, 5% manitol

Gene Information

• Gene Name: APOE apolipoprotein E [ Homo sapiens (human) ]
• Official Symbol: APOE
• Synonyms: APOE; apolipoprotein E; AD2, Alzheimer disease 2 (APOE*E4 associated, late onset); apo-E; apolipoprotein E3; AD2; LPG; LDLCQ5; MGC1571
• Gene ID: 348
• mRNA Refseq: NM_000041
• Protein Refseq: NP_000032
• MIM: 107741
• UniProt ID: P02649

Case Study

Case 1: Kreutzer E, et al. Pharm Res. 2024

This study investigated the isoform-specific effects of apolipoprotein E (apoE) on P-glycoprotein (P-gp) levels and activity in a human cerebral microvascular endothelial cell line (hCMEC/D3). The researchers used western blot to measure P-gp levels and rhodamine 123 uptake to assess function after exposing cells to recombinant apoE3 and apoE4 proteins, as well as astrocyte-conditioned media containing human apoE isoforms.

The results showed no significant differences in P-gp levels or function between cells treated with apoE3 and those treated with apoE4, indicating that apoE isoforms do not affect P-gp activity in this model. Positive controls SR12813 and PSC 833 confirmed the assay's sensitivity, as they significantly altered P-gp levels and function, respectively.

Fig1. Recombinant apoE3 (rE3) and apoE4 (rE4) do not directly modulate abundance of P-gp in hCMEC/D3 cells.

Fig2. Recombinant apoE3 (rE3) and recombinant apoE4 (rE4) do not affect P-gp function as assessed via rhodamine 123 (R123) accumulation.

Case 2: Atehortua L, et al. J Lipid Res. 2023

The previous research found that HDL can protect regulatory T cells (Treg) from apoptosis, contributing to its anti-inflammatory effects. Building on this, new findings reveal that HDL primarily interacts with memory Treg, especially the highly suppressive effector memory Treg, by inhibiting apoptosis in an Akt-dependent manner.

Researchers identified the protein component of HDL as the main factor mediating this effect, ruling out the most abundant HDL protein, apolipoprotein A-I (APOA1). HDL lacking APOE failed to protect effector memory Treg, highlighting APOE's importance. Reconstituted HDL particles with APOE and synthetic phospholipids significantly reduced Treg apoptosis, with APOE3 and APOE4 isoforms being the most effective. Lipid-free recombinant APOEs showed similar results, and binding studies indicated that lipid-free APOE3 specifically bound to memory Treg, not naive Treg.

Fig1. Caspase 3/7 expression of emTreg after treatment with rHDL-APOE(2–4)-POPC.

Fig2. Representative example of one cell for rhAPOE3 or rhAPOE3 + RAP.

Application

The main function of APOE is to transport lipids in the body, as part of plasma lipoproteins, mainly involved in the transport and metabolism of lipids in the body, affecting cholesterol levels, and associated with the risk of cardiovascular disease. APOE is associated with late-onset Alzheimer's disease (AD), cardiovascular diseases such as hypertension and atherosclerosis, obesity, and lipid metabolism.

In drug development, recombinant human APOE proteins can be used to screen and evaluate potential anti-AD drugs, as well as to study their effects on lipid metabolism and cell function. As a drug target, APOE-related drug development is ongoing to treat APOE-related diseases. Certain variants of the APOE gene act as biomarkers that may be associated with disease risk and response to treatment. There have been studies suggesting that the APOE4 allele may be associated with increased fertility, which is also worth investigating in animal models.

Fig1. Main functions of ApoE in the human body. (Monika Kacperczyk, 2021)