Background and Biological Significance of CACNA2D4

The CACNA2D4 gene encodes the alpha-2/delta-4 (α2δ-4) auxiliary subunit of voltage-gated calcium channels (VGCCs). This subunit is a member of the CACNA2D family, which includes four paralogs (α2δ-1 through α2δ-4). The α2δ subunits are glycosylphosphatidylinositol (GPI)-anchored extracellular proteins that associate non-covalently with the pore-forming α1 subunit and modulate channel expression levels, voltage-dependent activation, and inactivation kinetics.

CACNA2D4 is predominantly expressed in the retina and certain neuronal populations. Mutations and dysregulation of CACNA2D4 have been linked to retinal dysfunction and photoreceptor signaling defects, making it a relevant target for studies of inherited retinal diseases and sensory neuroscience. Recombinant Human CACNA2D4 Protein enables researchers to investigate protein–protein interactions, screen for modulatory compounds, and validate detection reagents in a defined biochemical context.

Materials Required

• Recombinant Human CACNA2D4 Protein (SKU: rp366829)
• Sterile, ultra-pure water or manufacturer-recommended reconstitution buffer
• Low-protein-binding microcentrifuge tubes (1.5 mL)
• Micropipettes and calibrated tips
• Bench-top microcentrifuge
• –20°C and –80°C freezers
• Dry ice or liquid nitrogen for aliquot snap-freezing
• SDS-PAGE or Western blot materials for quality verification (optional)
• Protein quantification reagent (e.g., BCA or Bradford assay kit)

Note: Consult the Certificate of Analysis (CoA) supplied with lot rp366829 for lot-specific reconstitution volume, concentration, and formulation details before proceeding.

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

Step 1 — Preparation

Allow the vial of Recombinant Human CACNA2D4 Protein to equilibrate to room temperature (18–25°C) for 10–15 minutes before opening. This minimises condensation and prevents introduction of moisture into the lyophilized cake.

Step 2 — Reconstitution

Add the volume of sterile ultra-pure water or recommended reconstitution buffer specified on the CoA directly to the vial. Gently swirl or pipette to mix; do not vortex vigorously, as shear forces can denature the protein. Allow to stand at room temperature for 5 minutes to ensure complete dissolution.

Step 3 — Clarification

Centrifuge the reconstituted solution at 5,000–10,000 × g for 2–5 minutes at 4°C to remove any insoluble particulates. Transfer the supernatant to a fresh, low-protein-binding tube.

Step 4 — Protein Quantification

Determine the protein concentration using a BCA or Bradford assay against a BSA standard curve. Compare the measured concentration with the CoA-stated value to confirm successful reconstitution.

Step 5 — Aliquoting

Divide the reconstituted protein into single-use aliquots appropriate for your experimental needs. Single-use aliquots prevent repeated freeze-thaw cycles that degrade protein activity and structural integrity. Label each tube clearly with the protein name, concentration, date, and lot number.

Step 6 — Storage

For short-term use (up to 1 week), store aliquots at 4°C. For long-term storage, snap-freeze aliquots using dry ice or liquid nitrogen and store at –80°C. Avoid storing at –20°C with frost-free (auto-defrost) freezers, as temperature cycling accelerates protein degradation. Do not refreeze thawed aliquots.

Quality Verification and Downstream Application Tips

SDS-PAGE / Western Blot Verification

Resolve a small aliquot (1–2 µg) of the reconstituted protein by SDS-PAGE under reducing conditions. Stain with Coomassie Blue or perform Western blot using an anti-CACNA2D4 antibody to confirm the expected molecular weight band and assess purity. The α2δ-4 subunit is a heavily glycosylated protein; apparent molecular weight on SDS-PAGE may differ from the calculated sequence-based molecular weight due to glycosylation.

Functional Assay Considerations

When using Recombinant Human CACNA2D4 Protein in binding or co-immunoprecipitation assays, titrate the protein concentration to establish linearity and avoid hook-effect artefacts. If incorporating the protein into lipid bilayer or cell-free expression systems, ensure buffer conditions (pH, ionic strength, detergent if required) are compatible with both CACNA2D4 and the partnering α1 subunit.

Carrier Protein Supplementation

For very dilute working solutions (below ~10 µg/mL), consider supplementing the buffer with a carrier protein such as 0.1% BSA (protease-free) to minimise adsorption losses to tube and plate surfaces.

Troubleshooting