Recombinant Human GPRASP1 Protein: Protocol & Usage Guide

Recombinant Human GPRASP1 Protein is a research-grade recombinant protein designed to support the study of G protein-coupled receptor (GPCR) downregulation, receptor internalization, and lysosomal sorting pathways in human cell biology.

Product Name

Recombinant Human GPRASP1 Protein

SKU

rp372286

Target Protein

GPRASP1 (G Protein-Coupled Receptor Associated Sorting Protein 1)

Species Origin

Human

Application

In vitro functional assays, protein interaction studies, GPCR downregulation research

Storage Recommendation

Store at -20°C or -80°C; avoid repeated freeze-thaw cycles

Background: GPRASP1 and GPCR Regulation

GPRASP1 (G Protein-Coupled Receptor Associated Sorting Protein 1), also known as GASP-1, is a member of the GASP protein family involved in the post-endocytic trafficking and lysosomal degradation of G protein-coupled receptors (GPCRs). Following agonist-induced internalization, GPCRs are sorted either for recycling back to the plasma membrane or for lysosomal degradation. GPRASP1 interacts with the C-terminal tails of multiple GPCRs and promotes their targeting to lysosomes, thereby contributing to sustained receptor downregulation.

GPRASP1 has been studied in the context of opioid receptor regulation, dopamine receptor trafficking, and cannabinoid receptor downregulation. Its role makes it a relevant target in addiction research, pain biology, and neuropsychiatric disease models. Recombinant Human GPRASP1 Protein enables researchers to investigate these interactions in defined biochemical systems.

Reconstitution Protocol

Follow these steps to reconstitute Recombinant Human GPRASP1 Protein prior to use:

1. Centrifuge: Briefly centrifuge the vial (1,000–2,000 × g, 30 seconds) before opening to consolidate lyophilized material at the bottom of the tube.
2. Reconstitution buffer: Reconstitute the protein in sterile, deionized water or the buffer recommended in the product datasheet (e.g., PBS, pH 7.4, containing carrier protein such as 0.1% BSA if required for stability). Add the appropriate volume as specified to achieve the desired stock concentration.
3. Gentle mixing: Mix gently by pipetting up and down or by gentle vortexing. Do not vigorously vortex, as this may cause protein denaturation or aggregation.
4. Incubation: Allow the solution to stand at room temperature for 5–10 minutes to ensure complete dissolution.
5. Aliquot: Divide the reconstituted protein into single-use aliquots to avoid repeated freeze-thaw cycles, which can compromise protein integrity and activity.

Note: Always refer to the specific lot Certificate of Analysis (CoA) for lot-specific reconstitution volumes and concentrations.

Storage and Stability Guidelines

Proper storage is critical to maintaining the activity and integrity of Recombinant Human GPRASP1 Protein:

• Short-term storage (up to 1 month): Store reconstituted protein at 4°C if it will be used within one month. Inclusion of a carrier protein (e.g., 0.1% BSA) can help prevent adsorption to tube surfaces and stabilize the protein during short-term refrigeration.
• Long-term storage: For storage beyond one month, aliquot the protein and store at -20°C or preferably -80°C. At -80°C, the protein is expected to remain stable for up to 12 months from the date of receipt when stored properly.
• Avoid freeze-thaw cycles: Each freeze-thaw cycle may reduce protein activity. Use single-use aliquots to prevent repeated thawing.
• Lyophilized form: If the product is provided in lyophilized form, store at -20°C until reconstitution. Lyophilized protein is generally more stable than the reconstituted form during long-term storage.

Disclaimer: Specific stability data should be confirmed from the product datasheet and CoA. Review flags have been added for any lot-specific stability claims.

Experimental Applications and Handling Tips

Recombinant Human GPRASP1 Protein is suitable for multiple research applications:

• Protein-protein interaction assays: GPRASP1 can be used in pull-down assays, co-immunoprecipitation, or surface plasmon resonance (SPR) experiments to characterize its interactions with GPCR C-terminal domains.
• Biochemical characterization: Use in enzyme-linked immunosorbent assay (ELISA)-based binding studies or in vitro binding assays to map functional domains.
• Cell-free systems: Suitable as a control or functional component in cell-free transcription/translation systems or reconstituted trafficking assays.
• Western blot standard: May be used as a positive control or molecular weight standard in Western blot experiments targeting GPRASP1.

Handling tips:

• Always work on ice when handling the protein to minimize activity loss.
• Use low-binding microcentrifuge tubes to reduce protein adsorption to tube surfaces.
• Centrifuge briefly before use if aggregates are visible.
• Determine optimal working concentration empirically, as this will vary by assay format and experimental conditions.

Quality Control and Verification

Aladdin Scientific's Recombinant Human GPRASP1 Protein (SKU: rp372286) undergoes quality control testing to ensure consistency and reliability:

• Purity assessment: Purity is typically evaluated by SDS-PAGE under reducing conditions. Consult the product CoA for lot-specific purity data.
• Identity verification: Protein identity may be confirmed by Western blot using a validated anti-GPRASP1 antibody.
• Endotoxin testing: Endotoxin levels are measured to ensure suitability for sensitive cell-based assays. Refer to the CoA for lot-specific endotoxin levels.
• Functional activity: Where applicable, functional activity is assessed using relevant binding or activity assays. Specific functional data should be confirmed from the product datasheet.

For the most accurate and up-to-date quality control data, always refer to the Certificate of Analysis supplied with each lot of product. Contact Aladdin Scientific technical support for additional information or troubleshooting assistance.

Frequently asked questions

What is GPRASP1 and why is it important in GPCR research?

GPRASP1 (G Protein-Coupled Receptor Associated Sorting Protein 1) is a protein that regulates the post-endocytic fate of GPCRs by promoting their lysosomal degradation rather than recycling. It plays a key role in sustained receptor downregulation, making it relevant to studies of opioid, dopamine, and cannabinoid receptor biology.

How should I reconstitute Recombinant Human GPRASP1 Protein?

Briefly centrifuge the vial before opening, then reconstitute with sterile deionized water or the recommended buffer (e.g., PBS pH 7.4 with 0.1% BSA) to the volume specified in the CoA. Mix gently and allow to stand at room temperature for 5–10 minutes before aliquoting and storing at -80°C.

How many freeze-thaw cycles can Recombinant Human GPRASP1 Protein withstand?

As a general best practice, recombinant proteins should be aliquoted into single-use volumes to avoid repeated freeze-thaw cycles. Each freeze-thaw event can degrade protein integrity and reduce activity. We recommend using each aliquot once and discarding any unused portion.

What applications is Recombinant Human GPRASP1 Protein validated for?

Recombinant Human GPRASP1 Protein is suitable for protein-protein interaction studies (pull-down, co-IP, SPR), in vitro binding assays, Western blot as a positive control, and cell-free system experiments. Specific validated applications should be confirmed in the product datasheet and CoA for each lot.

Can Recombinant Human GPRASP1 Protein be used in cell-based assays?

While GPRASP1 is primarily used in biochemical and binding assays, its suitability for cell-based applications depends on endotoxin levels and formulation. Check the CoA for endotoxin specifications and consult Aladdin Scientific technical support if you plan to use it in cell-based systems.

References

1. Whistler JL et al. Modulation of postendocytic sorting of G protein-coupled receptors. Science. 2002;297(5581):615-620. doi:10.1126/science.1073308
2. Martini L, Whistler JL. The role of mu opioid receptor desensitization and endocytosis in morphine tolerance and dependence. Curr Opin Neurobiol. 2007;17(3):308-313. doi:10.1016/j.conb.2007.04.001
3. Tappe-Theodor A et al. A molecular basis of analgesic tolerance to cannabinoids. J Neurosci. 2007;27(15):4165-4177. doi:10.1523/JNEUROSCI.5648-06.2007

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