The farnesoid X receptor (FXR) is a ligand-activated transcription factor that functions as a receptor for bile acids (BAs) such as chenodeoxycholic acid (CDCA), lithocholic acid, deoxycholic acid, and allocholic acid. FXR plays a critical role in maintaining BA homeostasis by regulating genes involved in BA synthesis, conjugation, and enterohepatic circulation. It also modulates lipid and glucose homeostasis and contributes to the innate immune response.
FXR forms a heterodimer with RXR, binding predominantly to FXR response elements (FXREs) containing inverted repeats (IR-1) or direct repeat (DR1) sites. In the liver, FXR activates transcription of NR0B2 (SHP), repressing CYP7A1 and CYP8B1, which are key enzymes in BA synthesis. FXR also induces transcription of MAFG, further regulating BA synthesis, and activates genes such as SLC27A5/BACS, BAAT, ABCB11/BSEP, ABCC2/MRP2, and ABCB4, which are involved in BA conjugation and export.
In the intestine, FXR induces FGF19 expression, which represses hepatic CYP7A1 and coordinates the expression of KLB (beta-klotho). FXR regulates lipid metabolism by repressing de novo lipogenesis (via NR0B2/SHP-mediated inhibition of SREBF1), promoting HDL formation and uptake, and modulating VLDL assembly and LDL clearance. Additionally, FXR influences glucose homeostasis by regulating hepatic gluconeogenesis and glycogen synthesis and modulates glucose-stimulated insulin secretion and insulin resistance.
FXR also plays an essential role in innate immunity, protecting the intestinal epithelial barrier, reducing bacterial overgrowth, and down-regulating inflammatory cytokine expression. It mediates anti-inflammatory effects in liver and intestinal inflammation by trans-repressing TLR4-induced cytokine expression and inhibiting pro-inflammatory NF-κB signaling.
| Product Name | Recombinant Human Bile Acid Receptor (NR1H4) Protein (His-SUMO) |
| Accession | Q96RI1 |
| Purity | Greater than 90% as determined by SDS-PAGE. |
| Host Species | Human |
| Gene | NR1H4 |
| Source | E.coli |
| Protein Expression Range | 1-476aa |
| Tag | N-6His-SUMO |
| Molecular Mass | 70.7kDa |
| Form | Liquid or Lyophilized powder |
| Buffer | Liquid form: default storage buffer is Tris/PBS-based buffer, 5%-50% glycerol. Lyophilized powder form: the buffer before lyophilization is Tris/PBS-based buffer, 6% Trehalose, pH 8.0. |
| Storage | 1. Store at -20¡«C/-80¡«C upon receipt, aliquoting is necessary for mutiple use. 2. Avoid repeated freeze-thaw cycles. 3. Store working aliquots at 4¡«C for up to one week. 4. In general, protein in liquid form is stable for up to 6 months at -20¡«C/-80¡«C. Protein in lyophilized powder form is stable for up to 12 months at -20¡«C/-80¡«C. |
