What Is FRRS1L and Why Is It Scientifically Relevant?

FRRS1L (Ferric-Chelate Reductase 1-Like protein), also known as CPTP or C9orf4, is a transmembrane protein encoded by the FRRS1L gene in humans. Despite its sequence homology to ferric-chelate reductases, FRRS1L's primary characterized function in neurons is as an auxiliary subunit of AMPA-type ionotropic glutamate receptors (AMPARs).

AMPA receptors are the principal mediators of fast excitatory neurotransmission in the central nervous system. FRRS1L associates with AMPAR complexes—alongside other auxiliary subunits such as TARPs and CNIH proteins—to modulate receptor trafficking, gating kinetics, and synaptic localization. Loss-of-function mutations in FRRS1L have been linked to severe neurodevelopmental disorders including epileptic encephalopathy, underlining its physiological importance.

Recombinant Human FRRS1L Protein (rp367838) enables researchers to investigate FRRS1L protein interactions, validate antibodies, and conduct biochemical studies outside the complexity of the native cellular environment.

Product Specifications and Quality Attributes

Aladdin Scientific's Recombinant Human FRRS1L Protein (rp367838) is produced using a recombinant expression system to ensure consistent lot-to-lot quality. Key specification details relevant to experimental planning include:

• Source: Recombinant expression; specific host system should be confirmed on the current datasheet or by contacting technical support, as expression host (e.g., E. coli, HEK293, baculovirus/insect cells) affects post-translational modifications and folding.
• Purity: Research-grade; exact purity percentage should be verified against the current Certificate of Analysis (CoA) supplied with each lot.
• Format: Supplied as a purified protein in a suitable buffer; confirm buffer composition and protein concentration from the product datasheet.
• Molecular Weight: Consistent with the predicted molecular weight of FRRS1L; verify the precise value from the CoA, as tags and processing may alter apparent MW on SDS-PAGE.

Always refer to the lot-specific CoA for purity, concentration, and SDS-PAGE data before use.

Reconstitution, Handling, and Storage Guidelines

Proper handling of Recombinant Human FRRS1L Protein is essential to maintain activity and integrity throughout your experiments.

Reconstitution

If supplied in lyophilized form, reconstitute the protein with the volume of sterile, ultrapure water or buffer recommended on the product datasheet. Allow the vial to equilibrate to room temperature before opening, and centrifuge briefly to collect any material from the cap or sides. Mix gently by pipetting; do not vortex, as this can denature the protein.

Storage

• Store at -80 °C for long-term stability.
• For short-term use (days), aliquots may be stored at -20 °C.
• Avoid repeated freeze-thaw cycles, which can cause aggregation and loss of activity. Prepare single-use aliquots upon first thaw.
• Do not store in frost-free freezers that cycle temperature.

Working Conditions

Keep the protein on ice during experimental setup. Use low-binding microcentrifuge tubes to minimize adsorption losses at low concentrations. If carrier protein (e.g., 0.1% BSA) is acceptable in your assay, it can help stabilize dilute solutions.

Experimental Applications and Assay Compatibility

Recombinant Human FRRS1L Protein (rp367838) is suitable for a range of in vitro research applications:

• Protein–Protein Interaction Studies: FRRS1L's role as an AMPAR auxiliary subunit makes it a key target for pull-down assays, co-immunoprecipitation controls, and surface plasmon resonance (SPR) or bio-layer interferometry (BLI) binding assays to characterize interactions with AMPAR subunits (GluA1–4) or other complex partners.
• Antibody Validation: Use as a positive control antigen in Western blot, ELISA, or dot blot experiments to validate anti-FRRS1L antibodies.
• Biochemical Characterization: Enzyme activity assays (noting that reductase activity under physiological conditions is not well established), circular dichroism (CD) spectroscopy for secondary structure confirmation, and thermal shift assays for stability profiling.
• Structural Studies: Provides material for crystallography or cryo-EM sample preparation in combination with AMPAR complex components.
• Drug Discovery: Serves as a biochemical tool to screen small molecules that may modulate AMPAR complex assembly or FRRS1L interactions.

Confirm suitability for each specific assay format by reviewing the product datasheet or contacting Aladdin Scientific technical support.

Troubleshooting Common Issues

The following guidance addresses frequently encountered problems when working with Recombinant Human FRRS1L Protein:

• Low or No Signal in Western Blot: Confirm the anti-FRRS1L antibody is validated for the denatured (SDS-PAGE) form of the protein. Check that the correct amount of protein was loaded and that transfer efficiency was adequate. Verify molecular weight matches the expected value on the CoA.
• Protein Aggregation: Aggregation is often caused by repeated freeze-thaw cycles or improper storage. Centrifuge the thawed protein at high speed (e.g., 14,000 × g for 10 min at 4 °C) to pellet aggregates before use. Ensure working solutions are kept on ice.
• Loss of Activity: Verify storage temperature, number of freeze-thaw cycles, and buffer composition. Some proteins require specific cofactors or reducing agents (e.g., DTT or β-mercaptoethanol) to maintain activity; check the datasheet for any such requirements.
• Unexpected Band Size on SDS-PAGE: Recombinant proteins with affinity tags or signal peptide processing may run differently than predicted from the canonical sequence. Refer to the CoA for the expected apparent MW under the supplied conditions.
• Binding Assay Inconsistencies: Ensure both interaction partners are in compatible buffers at appropriate pH and salt concentrations. BSA or other blocking agents may be needed to reduce non-specific binding.

If issues persist, contact Aladdin Scientific technical support with your lot number and experimental details.