| Field | Specification |
|---|---|
| Mfr No | |
| Activity | |
| Alternative Names | hToll (CD_antigen: CD284) |
| Conjugate | |
| Endotoxin Level | |
| Expression System | |
| Form | Liquid or Lyophilized powder |
| Molecular Weight | |
| Product Type | |
| Protein Length | |
| Purity | |
| Reconstitution | |
| Species | |
| Storage | |
| Target | |
| UniProt # |
Overview
This Recombinant Protein provides recombinant TLR4 from Homo sapiens (Human), produced in E.coli (region 27-631aa). It is commonly used as a defined reagent for assay development, binding studies, and mechanistic research (RUO).
Key elements and design rationale
- Region: 27-631aa (domain boundaries can affect binding/activity readouts).
- Expression host: E.coli (may differ from native PTMs/processing).
- Tag(s): His (supports purification/detection; consider tag effects in controls).
Biological background
Also reported as hToll (CD_antigen: CD284). Cooperates with LY96 and CD14 to mediate the innate immune response to bacterial lipopolysaccharide. Acts via MYD88, TIRAP and TRAF6, leading to NF-kappa-B activation, cytokine secretion and the inflammatory response. Also involved in LPS-independent inflammatory responses triggered by free fatty acids, such as palmitate, and Ni2+. Responses triggered by Ni2+ require non-conserved histidines and are, therefore, species-specific. Both M.tuberculosis HSP70 and HSP65 act via this protein to stimulate NF-kappa-B expression. In complex with TLR6, promotes sterile inflammation in monocytes/macrophages in response to oxidized low-density lipoprotein or amyloid-beta 42. In this context, the initial signal is provided by oxLDL- or amyloid-beta 42-binding to CD36. This event induces the formation of a heterodimer of TLR4 and TLR6, which is rapidly internalized and triggers inflammatory response, leading to the NF-kappa-B-dependent production of CXCL1, CXCL2 and CCL9 cytokines, via MYD88 signaling pathway, and CCL5 cytokine, via TICAM1 signaling pathway, as well as IL1B secretion. Binds electronegative LDL (LDL-) and mediates the cytokine release induced by LDL-. Stimulation of monocytes in vitro with M.tuberculosis PstS1 induces p38 MAPK and ERK1/2 activation primarily via TLR2, but also partially via this receptor.
Research relevance and current trends
- Quantitative mapping of ligand/receptor signaling to downstream phospho- and transcriptional programs.
- Use of recombinant standards to improve assay calibration and cross-study comparability.
Cooperates with LY96 and CD14 to mediate the innate immune response to bacterial lipopolysaccharide. Acts via MYD88, TIRAP and TRAF6, leading to NF-kappa-B activation, cytokine secretion and the inflammatory response. Also involved in LPS-independent inflammatory responses triggered by free fatty acids, such as palmitate, and Ni2+. Responses triggered by Ni2+ require non-conserved histidines and are, therefore, species-specific. Both M.tuberculosis HSP70 and HSP65 act via this protein to stimulate NF-kappa-B expression. In complex with TLR6, promotes sterile inflammation in monocytes/macrophages in response to oxidized low-density lipoprotein or amyloid-beta 42. In this context, the initial signal is provided by oxLDL- or amyloid-beta 42-binding to CD36. This event induces the formation of a heterodimer of TLR4 and TLR6, which is rapidly internalized and triggers inflammatory response, leading to the NF-kappa-B-dependent production of CXCL1, CXCL2 and CCL9 cytokines, via MYD88 signaling pathway, and CCL5 cytokine, via TICAM1 signaling pathway, as well as IL1B secretion. Binds electronegative LDL (LDL-) and mediates the cytokine release induced by LDL-. Stimulation of monocytes in vitro with M.tuberculosis PstS1 induces p38 MAPK and ERK1/2 activation primarily via TLR2, but also partially via this receptor.
Common research applications
- Standard curve or spike-in reference for quantitative assays involving TLR4
- Binding interaction studies (e.g., SPR/BLI or plate-based binding formats)
- Cell-based stimulation studies with downstream marker readouts (conceptual)
Notes for experimental interpretation
- Recombinant constructs may not capture all native isoforms or PTMs.
- Consider tag- or host-related effects when interpreting binding or activity.
- Use appropriate blanks and matrix/control concepts to separate signal from background.
What is protein expression and purification?
Why is there no/low protein expression?
b. Rare codons. You should optimize codons, use strains supplementing rare codons, induce at lower temperature or grow in poor media.
c. Protein toxicity. You should use promoters with tighter regulation or lower plasmid copy number. Use pLysS/pLysE bearing strains in T7-based systems or strains that are better for the expression of toxic proteins. Start induction at high OD and shorten induction time. Add glucose when using expression vectors containing lac-based promoters.
How to avoid inclusion bodies and improve soluble expression?
b. Incorrect disulfide bond formation. You should add fusion partners, including thioredoxin, DsbA, DsbC. Clone in a vector containing secretion signal peptide to cell periplasm. Use gamiB (DE3)strains with oxidative cytoplasmic environment. Lower inducer concentration and induction temperature.
c. Incorrect folding. You should use a fusion partner. Co-express with molecular chaperones. Use strains with cold-adapted chaperones. Supplement media with chemical chaperones and cofactors. Reduce the inducer concentration and add fresh media. Induce for a shorter time at low temperature.
Why is the molecular weight of protein smaller than the predicted?
b. Imbalanced translation process of fusion protein. You should change another fusion tag or move fusion tag to C-terminal. You should induce for a shorter time at low temperature or change to poor media.
c. Protein degradation. You should replace specific protease sites. Use protease deficient strains. Induce at high OD. You should induce for a shorter time at low temperature or use protease inhibitors when breaking cells.
Why is the actual band size different from the predicted?
b. Post-translational cleavage. Many proteins are synthesized as pro-proteins, and then cleaved to give the active form.
c. Splice variants. Alternative splicing may create different sized proteins from the same gene.
d. Relative charge. The composition of amino acids have different relative charge which will affect the electrophoretic mobility.
e. Multimers such as dimerisation of a protein. This is usually prevented in reducing conditions, although strong interactions can result in the appearance of higher bands.
f. Protein structure such as disulfide bond, protein secondary structure or protein 3D structure formation.
g. Hydrophobic proteins, such as transmembrane proteins, may have difficulties in migrating into the gel, and thus resulting in different multi-banded patterns.
How to express a protein with bioactivity? Why is the protein inactive?
a. Low solubility of the protein. You should fuse desired protein to a fusion partners and lower temperature.
b. Lack of essential post translational modification. You should change another expression system.
c. Incomplete folding. You should use a fusion partner and use strains with cold-adapted chaperones. Co-express with molecular chaperones at lower temperature. Monitor disulfide bond formation and allow further folding in vitro.
d. Mutations in cDNA. You should sequence plasmid before and after induction or use a recA− strain to ensure plasmid stability. Transform E. coli before each expression round.
Why are our protein products almost invisible in pipes?
Tips: Before opening the lid, we recommend to centrifuge in a small centrifuge for 20-30 seconds firstly to ensure that the contents are on the bottom of the tube. Our quality control steps ensure that the amount of protein contained in each tube is accurate, although sometimes you can’t see the protein powder, but the protein content in the tube is still very accurate.
How is the protein purified? Is the purity guaranteed?
Although we guarantee a minimum purity standard of >85%, some of the proteins we prepared have a purity of 95% or even 97%.
How should I reconstitute and store the products?
As for short-term storage or usage, please use sterile deionized water to completely reconstitute proteins to 0.1-1.0 mg/mL. Aliquot after 10-15 minutes if needed and store at 4℃.
As for long-term storage, the cytokines or recombinant proteins are recommended to add 5-50% of glycerol (final concentration) and aliquot for long-term storage at -20℃/-80℃. Our default final concentration of glycerol is 50%. Customers could use it as reference.
What types of tags do you use for fusion?
What is the impact of a given tag type and any potential biological activity of the protein?
Can you remove the endotoxin?
Can you offer aseptic manufacture processing?
How to determine species cross-reactivity of cytokines?
b. Many mouse cytokines may also have effect on human cells, however, the activity may be lower than the corresponding human cytokines.
c. One of the few human cytokines will be more active than corresponding mouse cytokines when acting on mouse cells, such as IL-7.
d. Interferon, GM-CSF, IL-3 and IL-4 and other cytokines are species-specific and almost have no activity on non-homologous cells.
e. In contrast, fibroblast growth factor (FGF) and neurotrophin are highly conserved and both have good activity on cells of different species.
What is the general preservative? Which kind of preservative do you usually add?
What is the general protectant? What kind of protectant do you usually add?
Can’t Find What You’re Looking For? We can help you source the best match or customize a recombinant protein solution for your study. Options may include species (human/mouse/rat), protein region/domain (full-length vs fragment), tag or label (His/GST/FLAG/biotin/fluorescent), expression system (E. coli/HEK293/insect), purity grade, formulation (buffer, carrier-free, glycerol-free), activity/functional validation (binding or enzymatic assays), endotoxin level (low-endotoxin for cell-based work), mutants/variants (point mutations, isoforms), and bulk or custom packaging. Click Talk to a Scientist to submit a request form, email us at support@biohippo.com, or explore our Research Services for additional support. Our team will be in contact with you shortly.
TLR4 rs1927914 polymorphism contributes to serum TLR4 levels in patients with aortic aneurysm
T Li,Experimental and Molecular Pathology,2021
Higher Levels of Triglyceride, Fatty Acid Translocase, and Toll-Like Receptor 4 and Lower Level of HDL-C in Pregnant Women with GDM and Their Close Correlation with Neonatal Weight
Jianli Zhou,Gynecol Obstet Invest,2021
