CALR Antibody / Calreticulin

Overview

CALR Antibody / Calreticulin is an antibody targeting CALR, raised in Rabbit for protein detection and localization studies where these specifications are required.

Key elements and design rationale

• Target: CALR (reported localization: Cytoplasm, cell membrane).
• Antibody identity: Polyclonal (rabbit origin); Rabbit IgG.
• Conjugate/label: Unconjugated (affects detection chemistry and multiplex compatibility).
• Format: Antigen affinity purified.
• Species reactivity: Human, Mouse, Rat.
• Listed applications: WB, IHC-P, FACS, ELISA (refer to on-page specifications for application-specific guidance).

Biological background

Calreticulin, also known as calregulin, CRP55, CaBP3, calsequestrin-like protein, and endoplasmic reticulum resident protein 60 (ERp60) is a protein that in humans is encoded by the CALR gene. It is mapped to 19p13.13. Calreticulin is a multifunctional protein that acts as a major Ca(2+)-binding (storage) protein in the lumen of the endoplasmic reticulum. It is also found in the nucleus, suggesting that it may have a role in transcription regulation. Calreticulin binds to the synthetic peptide KLGFFKR, which is almost identical to an amino acid sequence in the DNA-binding domain of the superfamily of nuclear receptors. Calreticulin binds to antibodies in certain sera of systemic lupus and Sjogren patients which contain anti-Ro/SSA antibodies, it is highly conserved among species, and it is located in the endoplasmic and sarcoplasmic reticulum where it may bind calcium. The amino terminus of calreticulin interacts with the DNA-binding domain of the glucocorticoid receptor and prevents the receptor from binding to its specific glucocorticoid response element. Calreticulin can inhibit the binding of androgen receptor to its hormone-responsive DNA element and can inhibit androgen receptor and retinoic acid receptor transcriptional activities in vivo, as well as retinoic acid-induced neuronal differentiation. Thus, calreticulin can act as an important modulator of the regulation of gene transcription by nuclear hormone receptors. Systemic lupus erythematosus is associated with increased autoantibody titers against calreticulin but calreticulin is not a Ro/SS-A antigen. Earlier papers referred to calreticulin as an Ro/SS-A antigen but this was later disproven. Increased autoantibody titer against human calreticulin is found in infants with complete congenital heart block of both the IgG and IgM classes.

Research relevance and current trends

• Comparative expression profiling across cell types, tissues, or perturbations (e.g., drug treatment, genetic editing, or differentiation).
• Subcellular localization and trafficking studies, including co-localization with pathway markers in microscopy-based assays.
• Integration of protein-level measurements with transcriptomics or proteomics to relate abundance to regulation and phenotype.

Common research applications

• Western blotting: researchers commonly compare relative signal levels across conditions and use appropriate negative/positive controls for interpretation.
• Immunohistochemistry: researchers commonly compare relative signal levels across conditions and use appropriate negative/positive controls for interpretation.
• Flow cytometry: researchers commonly compare relative signal levels across conditions and use appropriate negative/positive controls for interpretation.
• ELISA: researchers commonly compare relative signal levels across conditions and use appropriate negative/positive controls for interpretation.

Interpretation should account for antibody-dependent factors such as epitope accessibility, isoforms, and sample preparation differences across workflows.

Notes for experimental interpretation

• Isoforms and PTMs: many targets have multiple isoforms and post-translational modifications that can shift apparent signal or localization; interpret bands/signals accordingly.
• Epitope context: binding can depend on protein conformation and sample processing; region information in the title/immunogen can help anticipate what may be detected.
• Species differences: predicted or validated reactivity may vary by ortholog sequence and sample context; confirm in your model system.
• Control concepts: include negative controls (no-primary/isotype), and where possible genetic controls (KO/KD) or independent antibodies to strengthen conclusions.

Customization & Add-ons: Can’t find the antibody you need—or require a custom format for your assay? We can help you source the best match or support custom antibody solutions for diverse research needs, including species and isotype selection, conjugations and labeling (e.g., HRP/AP, biotin, fluorophores), purification grade options (Protein A/G, affinity purified), formulation preferences (buffer selection, carrier-free, glycerol-free), custom concentrations and aliquoting, low-endotoxin options for cell-based work, and application-focused QC/validation support (project dependent). Click Talk to a Scientist to submit a request, email us at support@biohippo.com, or explore our Research Services for additional support—our team will follow up with feasibility details and next steps.