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  • Recombinant Human TSHR Protein (His Tag)

Recombinant Human TSHR Protein (His Tag)

High-purity extracellular domain (ECD) for Graves' disease diagnostics, autoantibody screening, and CAR-T discovery.

The Human TSHR Protein is a valuable research reagent in endocrinology and autoimmune thyroid disease. TSHR is the primary autoantigen in Graves’ disease, and recombinant TSHR proteins are used in antibody-binding studies and assay development. TSHR has also been explored as a target in thyroid cancer research, though its therapeutic role remains less established than in autoimmune thyroid disease.

1. Target Overview: TSHR Biology & Autoimmunity

The Thyroid-Stimulating Hormone Receptor (TSHR) is a G-protein coupled receptor (GPCR) predominantly expressed on the basolateral membrane of thyroid follicular cells. It is responsible for regulating thyroid growth and the synthesis of thyroid hormones (T3 and T4) upon binding to its natural ligand, TSH.

Structurally, TSHR is unique among GPCRs due to its massive, highly glycosylated Extracellular Domain (ECD). This large leucine-rich repeat domain (LRR) is not only the binding site for endogenous TSH but also the primary immunogenic target in Autoimmune Thyroid Diseases (AITD).

Clinical Relevance in Graves' Disease: In Graves' disease, patients produce Thyroid Receptor Autoantibodies (TRAbs). Stimulating TRAbs bind directly to the TSHR ECD, mimicking TSH and causing chronic hyperthyroidism. Utilizing a properly folded TSH receptor extracellular domain protein is strictly required to detect these conformation-dependent autoantibodies in patient sera.

Emerging Role in Oncology: Beyond autoimmunity, TSHR is highly overexpressed in differentiated thyroid cancers. Recent breakthrough research has leveraged TSHR as a highly specific target for CAR-T cell therapies and antibody-drug conjugates (ADCs) in radioiodine-refractory thyroid tumors.

2. Technical Specifications (orb1098602)

To ensure absolute transparency and experimental reproducibility, the precise biochemical properties of our Recombinant Human TSHR Protein (His tag) are detailed below. This specific construct features the N-terminal region of the receptor optimized for robust in vitro assay performance.

Target / UniProt ID

Thyrotropin Receptor (TSHR) / P16473 (Human)

Expression Host

E. coli

Expressed Region

Amino acids 22-260

Molecular Weight

26.9 kDa

Tag Sequence

N-terminal His Tag

Purity

>90% as determined by SDS-PAGE gel analyses

Formulation & Buffer

Lyophilized from a 0.2 μm filtered solution in PBS with 5% trehalose, pH 7.4

Reconstitution & Storage

Reconstitute in sterile distilled water to 0.1-1 mg/ml without vortexing. Store at -20°C for 12 months (lyophilized) or 2-8°C for 1 month under sterile conditions after reconstitution.

3. Applications & Validated Assays

This TSHR His tag protein (orb1098602) has been rigorously tested and validated for key immunochemical applications. Its high purity and defined 22-260 amino acid expression region make it an excellent tool for targeted receptor studies.

  • Enzyme-Linked Immunosorbent Assay (ELISA): Validated for use in EIA protocols. This protein is ideal for coating microtiter plates to screen for antibodies that specifically recognize the N-terminal extracellular domain of human TSHR.
  • Western Blot (WB): Validated as a highly specific target for immunoblotting assays. It reliably resolves at its expected 26.9 kDa molecular weight, allowing researchers to confidently confirm the specificity of their primary anti-TSHR antibodies.
  • Antibody Generation: Utilizing a highly pure, E. coli-expressed recombinant fragment allows researchers to focus immune responses on the primary amino acid sequence (linear epitopes), making it a valuable immunogen for generating novel monoclonal or polyclonal antibodies.

4. Advanced Laboratory Workflows & Assay Integration

Beyond standard ELISA protocols, recombinant TSHR extracellular domain (ECD) is a versatile reagent that can be adapted into a range of complex, high‑throughput, and structural workflows, particularly when produced with appropriate mammalian‑like folding and glycosylation.

A

Multiplexed Autoantibody Screening (Luminex / Flow)

His‑tagged TSHR ECD can be immobilized on Ni‑NTA magnetic beads or similar surfaces to create customized capture assays. This approach can support multiplexed detection of TSHR‑reactive antibodies in low‑volume patient sera by flow cytometry or Luminex platforms, although the extent to which it distinguishes stimulating, blocking, and neutral TRAbs depends on assay design and validation.

B

Cell-Based "Decoy" Receptor Assays

In competitive cAMP‑based cell assays, soluble TSHR ECD can act as a binding competitor for TRAbs and TSH. By pre‑incubating patient sera or test compounds with the recombinant protein, researchers can probe the degree to which antibody‑mediated or ligand‑mediated signaling is blocked, providing one line of evidence for target specificity. However, robust decoy behavior is construct‑ and condition‑dependent and requires careful optimization.

C

Structural Biology (Cryo-EM & Crystallography)

High‑resolution structures of full‑length TSHR bound to autoantibodies such as M22 and K1‑70 have been obtained by cryo‑EM, confirming that the ECD can adopt native‑like conformations suitable for structural studies. Mammalian‑expressed, properly folded TSHR ECD fragments are therefore compatible with Cryo‑EM and crystallography workflows for antibody‑receptor complexes, although success still hinges on construct design, stability, and sample preparation.

5. Quality Control: What to Look For in TSHR Proteins

When sourcing recombinant GPCR domains, standard SDS-PAGE is insufficient to guarantee functional conformation.

Validation Metric

Methodology

Why It Matters for TSHR

Oligomeric State

SEC-HPLC (Size Exclusion Chromatography)

TSHR ECDs can form non‑functional aggregates; SEC‑HPLC confirms a predominantly monomeric, well‑folded state, with activity best verified by binding assays.

Glycosylation Profiling

PNGase F Digestion / Mass Spec

TSHR carries multiple N‑linked glycans; mammalian‑like glycosylation supports stability and some epitopes, but not all Graves’‑disease TRAbs strictly require native glycans.

Binding Affinity (KD)

Surface Plasmon Resonance (SPR)

SPR KD measurement confirms interaction with TSH or monoclonal antibodies, providing a quantitative functional benchmark; affinities typically lie in the nM range and vary by epitope and construct.

7. Buying Guidance: Selecting Your TSHR Protein

Not all recombinant proteins perform equally in functional assays. Follow this guidance to ensure you select the correct reagent for your workflow.

1

Why choose the Extracellular Domain (ECD)?

Full-length GPCRs are highly hydrophobic and notoriously difficult to express in soluble forms, often requiring detergent micelles. For autoantibody screening, SPR, and ELISA, the soluble TSHR ECD (aa 22-413) contains the complete functional binding pocket required without the aggregation issues of the transmembrane domains.

2

The Importance of Mammalian Expression (HEK293)

TSHR is a heavily glycosylated receptor. Proteins expressed in E. coli lack glycosylation, which often results in misfolding and failure to bind conformational autoantibodies. Selecting a HEK293 or CHO-expressed protein ensures native folding required for Graves' disease diagnostics.

3

Leveraging the His-Tag

The C-terminal His-tag is small (only 6 amino acids) and rarely interferes with protein folding, but its effect on stability and conformation should be verified for each construct. It allows for highly directed, uniform orientation when immobilizing the TSHR protein for ELISA on nickel-coated plates, maximizing the exposure of the active binding site.

8. Companion Bioreagents

Biorbyt offers a complete suite of reagents to complement your TSHR research, allowing you to build fully validated assays from a single trusted provider.

Primary Antibody Anti-TSHR Antibody Highly specific monoclonal antibody for detecting endogenous TSHR in thyroid tissue sections via IHC and WB. Active Protein Recombinant Human TSH (Thyrotropin) The natural heterodimeric ligand for TSHR. Ideal for use as a positive control in competitive binding assays. Detection Antibody Anti-His Tag Antibody (HRP) Directly conjugated secondary antibody for rapid, sensitive detection of the His-tagged TSHR protein in WB and ELISA. ELISA Kit Human TSHR Autoantibody ELISA Kit A ready-to-use competitive ELISA kit for quantifying TRAbs in human serum samples. 

9. Scientific Bibliography

The structural biology, clinical relevance, and expression criteria detailed on this page are meticulously fact-checked and supported by the following highly-cited peer-reviewed literature:

 

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