Calreticulin Recombinant Protein Antigen

• Reactivity: Hu
• Applications: AC

Calreticulin Recombinant Protein Antigen Summary

• Description: A recombinant protein antigen with a N-terminal His6-ABP tag corresponding to human Calreticulin
  
  

  Source: E.coli

  Amino Acid Sequence: EQNIDCGGGYVKLFPNSLDQTDMHGDSEYNIMFGPDICGPGTKKVHVIFNYKGKNVLINKDIRCKDDEFTHLYTLIVRPDNTYEVKIDNSQVESGSLEDDWDFLPPKKIKDPDASKPEDWDERAKIDDPTDS

  Fusion Tag: N-terminal His6ABP (ABP = Albumin Binding Protein derived from Streptococcal Protein G)

• Protein/Peptide Type: Recombinant Protein Antigen
• Gene: CALR
• Purity: >80% by SDS-PAGE and Coomassie blue staining

Applications/Dilutions

• Dilutions:
  • Antibody Competition 10-100 molar excess
• Application Notes: This recombinant antigen is only intended to be used as a blocking agent to confirm antibody specificity with the corresponding antibody, catalog number NBP2-48491It is purified by IMAC chromatography, and the expected concentration is greater than 0.5 mg/ml.For current lot information, including availability, please contact our technical support team click nb-technical@bio-techne.com.

Packaging, Storage & Formulations

• Storage: Store at -20C. Avoid freeze-thaw cycles.
• Buffer: PBS and 1M Urea, pH 7.4.
• Preservative: No Preservative
• Purity: >80% by SDS-PAGE and Coomassie blue staining

Alternate Names for Calreticulin Recombinant Protein Antigen

• Autoantigen Ro
• CALR
• Calregulin
• Calreticulin
• cC1qR
• CRP55
• CRT
• Endoplasmic reticulum resident protein 60
• epididymis secretory sperm binding protein Li 99n
• ERp60
• FLJ26680
• grp60
• HACBP
• HEL-S-99n
• RO
• Sicca syndrome antigen A (autoantigen Ro; calreticulin)
• SSA
• Vasostatin

Background

Calreticulin, also called CALR, is an endoplasmic reticulum (ER) protein that functions as a calcium (Ca2+) buffering molecular chaperone (1-3). Together with calnexin and ERp57, calreticulin has a critical role in protein folding and quality control of newly synthesized glycoproteins (1-3). Calreticulin has many diverse functions beyond Ca2+ binding, including cell adhesion, lectin binding, apoptosis, nuclear transport, antigen presentation, and immune response (1-3). Specifically, calreticulin is part of the peptide-loading complex that resides on the ER membrane and is responsible for antigen loading onto MHC class I molecules (1-3). Calreticulin protein has a theoretical molecular weight of 46 kDa and is 417 amino acids (aa) in length (1-3). The protein has three main domains: the N-terminal lectin-like domain, the proline-rich P-domain, and the acidic C-domain which is followed by an ER-retention KDEL signal sequence (1-3).

Given its role in multiple biological processes, it makes sense that calreticulin is implicated in both healthy and disease states. Studies have found that calreticulin mutations were present in patients with myeloproliferative neoplasms (MFN) and essential thrombocythaemia (ET) (4). Calreticulin expression is typically upregulated in most cancer lines, however it is downregulated in some tissues including cervical carcinomas, prostate cancer, and human colon adenocarcinoma (3). High expression of calreticulin on cancer cells is related to tumor cell phagocytosis and is often correlated with, and counteracted by, elevated CD47 expression to prevent cancer cell phagocytosis (3). Calreticulin mutations can serve as a major diagnostic biomarker for MFN and ET and additionally the calreticulin gene may be a potential target for cancer therapeutics (3,4).

References

1. Michalak, M., Groenendyk, J., Szabo, E., Gold, L. I., & Opas, M. (2009). Calreticulin, a multi-process calcium-buffering chaperone of the endoplasmic reticulum. The Biochemical Journal. https://doi.org/10.1042/BJ20081847

2. Fucikova, J., Spisek, R., Kroemer, G., & Galluzzi, L. (2021). Calreticulin and cancer. Cell Research. https://doi.org/10.1038/s41422-020-0383-9

3. Sun, J., Mu, H., Dai, K., & Yi, L. (2017). Calreticulin: a potential anti-cancer therapeutic target. Die Pharmazie. https://doi.org/10.1691/ph.2017.7031

4. Prins, D., Gonzalez Arias, C., Klampfl, T., Grinfeld, J., & Green, A. R. (2020). Mutant Calreticulin in the Myeloproliferative Neoplasms. HemaSphere. https://doi.org/10.1097/HS9.0000000000000333

Limitations

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Peptides and proteins are guaranteed for 1 year from date of receipt.

Bioinformatics

• Gene Symbol: CALR