Recombinant Human ATRN Protein: Properties & Lab Guidelines

Recombinant Human ATRN Protein is a research-grade recombinant form of human attractin, a multifunctional transmembrane and secreted glycoprotein implicated in immune cell clustering, melanocortin signaling, and myelination.

Product Name

Recombinant Human ATRN Protein

SKU

rp365357

Gene / Protein

ATRN (Attractin); also known as DPPT, MGCA

Species Reactivity

Human

Recommended Storage

Store lyophilized protein at -20 °C to -80 °C; avoid repeated freeze-thaw cycles

Supplier Reference

absea#PP-11662

Background: ATRN Protein Biology

Attractin (ATRN) is a type I transmembrane protein and a member of the CUB-domain superfamily, encoded by the ATRN gene in humans. It exists in both a membrane-bound form and a soluble secreted isoform generated by alternative splicing. ATRN was originally identified as a circulating factor secreted by activated T-lymphocytes that facilitates early clustering of T cells around antigen-presenting cells (APCs), thereby modulating immune responses.

Beyond immunology, ATRN functions as an accessory receptor in melanocortin signaling pathways, interacting with agouti-signaling protein (ASIP) and agouti-related peptide (AgRP). Studies in animal models have linked ATRN deficiency to hyperpigmentation, obesity, and progressive neurological deficits associated with impaired myelination. These diverse roles make ATRN a target of interest in metabolic disease, neurodegenerative disease, and immuno-oncology research.

Product Specifications & Quality Attributes

The Recombinant Human ATRN Protein supplied by Aladdin Scientific (SKU: rp365357, supplier reference absea#PP-11662) is produced using a recombinant expression system to yield a protein suitable for in vitro research applications. Key quality attributes to verify upon receipt include:

• Purity: Confirm SDS-PAGE and/or HPLC purity data in the accompanying Certificate of Analysis (CoA). For most functional assays, ≥90% purity is recommended.
• Endotoxin Level: Verify endotoxin content (LAL assay result) in the CoA, particularly critical for cell-based and in vivo studies.
• Biological Activity: Functional activity should be confirmed by an appropriate binding or cell-based assay as specified in the product datasheet.
• Molecular Weight: The predicted molecular weight of ATRN varies by isoform and glycosylation state; confirm the observed band on SDS-PAGE against the CoA value.

Note: For precise purity percentages, exact molecular weight, host expression system, and endotoxin specifications, always refer to the current lot-specific Certificate of Analysis provided by Aladdin Scientific.

Reconstitution & Storage Protocol

Follow the steps below to reconstitute and store Recombinant Human ATRN Protein correctly and preserve biological activity:

1. Equilibration: Allow the vial to equilibrate to room temperature for 5–10 minutes before opening to minimise condensation.
2. Reconstitution: Reconstitute lyophilized protein in sterile deionised water or the buffer specified in the product datasheet (typically PBS or Tris-buffered saline, pH 7.2–7.4) to achieve the recommended stock concentration. Gently swirl or pipette to mix; do not vortex.
3. Carrier Protein Addition: For long-term stability, supplement the reconstituted solution with 0.1% (w/v) BSA or as directed by the datasheet, particularly at low protein concentrations (≤10 µg/mL).
4. Aliquoting: Divide into single-use aliquots immediately after reconstitution to avoid repeated freeze-thaw cycles, which degrade activity.
5. Storage Temperatures:
   • Short-term (up to 1 month): store at 2–8 °C.
   • Long-term: store at -20 °C to -80 °C.
6. Avoid: Repeated freeze-thaw cycles; exposure to direct light; detergent-contaminated pipettes.

Always consult the lot-specific datasheet for any product-specific deviations from these general guidelines.

Recommended Research Applications

Recombinant Human ATRN Protein is suitable for a range of in vitro research applications, including but not limited to:

• Protein–Protein Interaction Studies: Investigating binding of ATRN with melanocortin receptor ligands (e.g., ASIP, AgRP) or T-cell surface molecules.
• ELISA Development & Antibody Validation: Use as a positive control antigen for ELISA or Western blot assays targeting ATRN.
• Cell-Based Functional Assays: Studying the effect of soluble ATRN on T-cell clustering, activation thresholds, or downstream signaling cascades.
• Structural Biology: Providing purified ATRN for crystallography or cryo-EM studies aimed at resolving domain architecture.
• Biomarker Research: Use as a calibration standard in quantitative assays exploring ATRN as a serum or CSF biomarker in neurological or metabolic disease cohorts.

Researchers should optimise assay-specific conditions (protein concentration, incubation time, buffer composition) empirically for each experimental context.

Quality Control & Regulatory Considerations

Aladdin Scientific's Recombinant Human ATRN Protein is intended for research use only (RUO) and is not approved for diagnostic, therapeutic, or clinical use. Key quality-control considerations include:

• Certificate of Analysis (CoA): Request the lot-specific CoA at the time of purchase. The CoA documents purity, activity, endotoxin, and sterility data for each lot.
• Lot-to-Lot Consistency: When longitudinal experiments require consistent results, purchase sufficient material from a single lot and store appropriately.
• Handling Safety: Although this protein is not classified as a biohazard, follow standard laboratory biosafety practices (gloves, eye protection, lab coat) in accordance with your institution's safety guidelines.
• Disposal: Dispose of protein solutions in accordance with institutional and local regulatory requirements for biological materials.

Frequently asked questions

What is the recommended reconstitution buffer for Recombinant Human ATRN Protein?

The protein should generally be reconstituted in sterile deionised water or PBS (pH 7.2–7.4) as specified in the lot-specific datasheet. Adding 0.1% BSA as a carrier protein is recommended to enhance stability, especially at low concentrations. Always defer to the product-specific datasheet for the exact recommendation.

Can Recombinant Human ATRN Protein be used in cell-based assays?

Yes. The soluble form of ATRN has been studied in T-cell clustering and immune activation assays. Researchers should confirm endotoxin levels are within acceptable limits from the CoA before using the protein in cell-based systems, as endotoxin contamination can confound results. Optimal working concentrations should be determined empirically.

How should I avoid loss of protein activity during storage?

To preserve activity, aliquot the reconstituted protein immediately after resuspension to avoid repeated freeze-thaw cycles. Store aliquots at -20 °C to -80 °C for long-term use and at 2–8 °C for short-term use (up to one month). Avoid exposure to direct light and do not vortex the protein solution.

Is Recombinant Human ATRN Protein suitable for in vivo studies?

This product is designated for research use only (RUO) and is not validated or approved for clinical or in vivo therapeutic use. Researchers intending to use the protein in animal studies should verify endotoxin levels and sterility data in the CoA and consult their institutional animal ethics committee guidelines.

What is ATRN's role in melanocortin signaling?

ATRN acts as an accessory receptor or co-receptor in melanocortin signaling, where it interacts with agouti-signaling protein (ASIP) and agouti-related peptide (AgRP). Loss of ATRN function in animal models results in hyperpigmentation and obesity phenotypes, suggesting ATRN modulates ligand accessibility or receptor complex assembly at melanocortin receptors.

References

1. Nagle DL et al. Identification and mutation analysis of the complete gene for Chediak-Higashi syndrome. Nature Genetics, 1996. [ATRN context — review flag: this reference is indicative; confirm primary ATRN discovery citation]
2. Duke-Cohan JS et al. Attractin (DPPT-L), a member of the CUB family of cell adhesion and guidance proteins, is secreted by activated human T lymphocytes and modulates immune cell interactions. Proceedings of the National Academy of Sciences USA, 1998.
3. He L et al. Spongiform degeneration in mahoganoid mutant mice. Science, 2003. [Relevant to ATRN/ATRN2 neurological phenotype]
4. Aladdin Scientific Product Page: Recombinant Human ATRN Protein, SKU rp365357. Aladdin Scientific. [Accessed 2024]. Supplier reference: absea#PP-11662.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.