Background: GRIN2C and Its Role in NMDA Receptor Biology

The GRIN2C gene encodes the GluN2C subunit (also designated NR2C) of the N-methyl-D-aspartate (NMDA) ionotropic glutamate receptor. NMDA receptors are tetrameric ligand-gated ion channels composed of obligatory GluN1 subunits in combination with GluN2 (A–D) or GluN3 subunits. The specific GluN2 subunit incorporated into the tetramer determines the receptor's pharmacological and biophysical properties, including magnesium block sensitivity, channel conductance, and deactivation kinetics.

GluN2C is predominantly expressed in cerebellar granule cells and in certain thalamic and olfactory neurons. Compared with GluN2A and GluN2B, GluN2C-containing receptors exhibit lower single-channel conductance and reduced sensitivity to voltage-dependent magnesium block, features that distinguish their physiological roles. Alterations in GRIN2C expression or function have been associated with schizophrenia susceptibility and other neuropsychiatric conditions, making this subunit a target of significant research interest.

Recombinant Human GRIN2C Protein provides a well-defined, research-grade source of this subunit for in vitro biochemical and cell-free studies, circumventing the challenges of isolating native protein from brain tissue.

Materials Required

• Recombinant Human GRIN2C Protein (Aladdin Scientific, SKU: rp368060)
• Sterile, nuclease-free water or reconstitution buffer as specified on product datasheet
• Microcentrifuge tubes (low-protein-binding, 0.5 mL or 1.5 mL)
• Micropipettes and calibrated tips
• Dry ice or liquid nitrogen for snap-freezing aliquots
• -80°C freezer for long-term storage
• Ice bucket or cooling block for on-bench handling
• Protein quantification reagents (e.g., BCA or Bradford assay kit)
• SDS-PAGE or Western blot consumables (for QC verification, if required)
• Relevant assay buffers appropriate to downstream application (binding, ELISA, functional assay)

Step-by-Step Protocol: Reconstitution, Aliquoting, and Storage

Step 1: Receipt and Initial Handling

Upon receipt, inspect the vial for integrity. If the protein is supplied lyophilized, store the unopened vial at -80°C until use. If supplied in liquid form, transfer immediately to -80°C. Allow the vial to equilibrate to room temperature for no more than 5 minutes before opening to minimise condensation.

Step 2: Reconstitution (Lyophilized Format)

Centrifuge the sealed vial briefly (1,000 × g, 30 seconds) to pellet any material from the cap. Add the recommended volume of sterile reconstitution buffer (refer to the product-specific datasheet for buffer composition and volume) slowly along the inner wall of the vial. Do not vortex. Gently pipette up and down or swirl carefully until fully dissolved. Allow to stand on ice for 5 minutes to ensure complete dissolution.

Step 3: Protein Quantification (QC Check)

Determine the protein concentration using a BCA or Bradford assay according to the manufacturer's instructions, using BSA as a standard. Compare the measured concentration to the value stated on the Certificate of Analysis (CoA). Discrepancies greater than 20% should be flagged for review.

Step 4: Aliquoting

Divide the reconstituted protein into single-use aliquots using low-protein-binding microcentrifuge tubes to prevent loss of material through adsorption. Aliquot sizes should reflect typical single-experiment usage volumes to avoid repeated freeze-thaw cycles. Snap-freeze each aliquot in liquid nitrogen or on dry ice.

Step 5: Storage

Store aliquots at -80°C. For short-term use within 48 hours, aliquots may be kept at 4°C. Do not expose to repeated freeze-thaw cycles as this will degrade protein integrity and activity. Refer to the product datasheet for the stated shelf life under recommended storage conditions.

Recommended Downstream Applications

Recombinant Human GRIN2C Protein is suitable for a range of biochemical and cell-free applications:

• SDS-PAGE and Western Blot: Confirm identity and purity of the recombinant protein; useful as a positive control in immunodetection experiments targeting GRIN2C.
• ELISA: Use as a coating antigen or standard to develop or validate antibody-based detection assays for GluN2C.
• Protein–Protein Interaction Studies: Investigate interactions between GRIN2C and other NMDA receptor subunits, scaffolding proteins (e.g., PSD-95), or regulatory proteins using pull-down or co-immunoprecipitation formats.
• Ligand Binding Assays: Study binding of glutamate, glycine co-agonists, or small-molecule modulators to the isolated subunit domain in cell-free settings.
• Structural Studies: The recombinant protein may serve as a component for biophysical characterisation methods such as size-exclusion chromatography (SEC), dynamic light scattering (DLS), or cryo-electron microscopy sample preparation.

Always optimise working concentrations empirically for each specific assay format.

Troubleshooting and Quality Considerations