Biological Background of CABP5

Calcium Binding Protein 5 (CABP5) is a member of the calmodulin superfamily and belongs to the neuronal calcium sensor (NCS) branch of EF-hand calcium-binding proteins. CABP5 is predominantly expressed in the retina, with notable localization in rod and cone photoreceptors as well as bipolar cells, where it plays a regulatory role in calcium-dependent signaling cascades.

Like other CaBP family members, CABP5 modulates the activity of voltage-gated calcium channels and other calcium-sensitive targets through direct protein–protein interactions. Its expression pattern and biochemical properties suggest involvement in the precise regulation of synaptic transmission and phototransduction within the retina. Research into CABP5 and related calcium sensors has broad implications for understanding sensory neuroscience, retinal physiology, and the molecular basis of visual processing disorders.

Product Characteristics and Quality Attributes

Aladdin Scientific's Recombinant Human CABP5 Protein (SKU: rp372663) is produced using recombinant expression technology to ensure consistent batch-to-batch quality. Recombinant production allows researchers to obtain a defined, well-characterized protein free from the variability associated with tissue-derived preparations.

Key quality considerations for recombinant proteins such as CABP5 include purity (typically assessed by SDS-PAGE and/or HPLC), biological activity, endotoxin levels (particularly important for cell-based assays), and accurate protein concentration determination. Researchers are advised to consult the product datasheet for lot-specific quality control data, including purity percentage, host expression system, tag information, formulation buffer composition, and recommended storage conditions.

Note: Specific numerical quality data (e.g., exact purity percentage, endotoxin limits, molecular weight) for rp372663 should be verified against the current product datasheet available from Aladdin Scientific.

Research Applications

Recombinant Human CABP5 Protein is a versatile research tool applicable across multiple experimental platforms:

• Calcium Signaling Studies: CABP5 can be used to interrogate its modulatory effects on voltage-gated calcium channels (e.g., Cav1 family L-type channels) in biochemical and cell-free reconstitution assays.
• Protein–Protein Interaction Assays: As a bait or prey protein in pull-down experiments, co-immunoprecipitation (co-IP), or surface plasmon resonance (SPR) studies to identify novel binding partners.
• Structural and Biophysical Studies: Suitable for circular dichroism (CD), isothermal titration calorimetry (ITC), or X-ray crystallography studies aimed at resolving calcium-dependent conformational changes.
• Retinal and Neuronal Research: Use as a positive control antigen in immunoassays or Western blot validation experiments focused on retinal or neuronal tissue samples.
• Drug Discovery: Screening assays designed to identify small molecules that modulate CABP5–channel interactions relevant to retinal disease or neurological conditions.

Handling, Storage, and Reconstitution Guidelines

Proper handling of recombinant proteins is essential to preserve activity and ensure reproducible experimental results. The following general best-practice guidelines apply to Recombinant Human CABP5 Protein:

• Storage: Store lyophilized or liquid protein preparations according to the conditions specified on the product datasheet (typically –20°C or –80°C for long-term storage). Avoid repeated freeze-thaw cycles, as these can lead to protein aggregation and loss of activity.
• Reconstitution: If supplied in lyophilized form, reconstitute using the buffer and volume specified in the datasheet. Allow the vial to equilibrate to room temperature before opening. Gently mix by pipetting; do not vortex.
• Working Aliquots: Prepare single-use aliquots to minimize freeze-thaw cycles. Store working aliquots at 4°C for short-term use (typically up to one week).
• Protein Quantification: Verify protein concentration upon reconstitution using a validated assay (e.g., BCA or Bradford assay) if high precision is required.
• Carrier Protein: For low-concentration working solutions, consider adding BSA (0.1–0.5%) to stabilize the protein and prevent adsorption to tube surfaces.

Always consult the lot-specific Certificate of Analysis (CoA) and product datasheet provided by Aladdin Scientific for definitive storage and handling instructions.

Frequently Cited Research Context and Relevance

CABP5 research is situated within the broader field of neuronal calcium sensor proteins, a group that includes calmodulin, recoverin, and the CaBP/caldendrin subfamily. These proteins are of significant interest because calcium is a ubiquitous second messenger that controls diverse neuronal functions including neurotransmitter release, synaptic plasticity, and gene expression.

Within the retina, precise calcium regulation is particularly critical because photoreceptors must rapidly adapt to changing light conditions. Calcium sensors such as CABP5 modulate voltage-gated calcium channels at the photoreceptor ribbon synapse, influencing the fidelity of visual signal transmission to downstream bipolar and ganglion cells. Dysregulation of these pathways has been associated with retinal degenerative conditions, making CABP5 and its interaction partners potential targets for therapeutic investigation.

Researchers working on retinal physiology, channelopathies, or calcium-dependent neurodegeneration may find Recombinant Human CABP5 Protein a valuable addition to their experimental toolkit.