Recombinant Human Calreticulin Protein (Fc Tag)

Beta LifeScience SKU/CAT #: BLPSN-0526

Recombinant Human Calreticulin Protein (Fc Tag)

Beta LifeScience SKU/CAT #: BLPSN-0526
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Product Overview

Tag Fc
Host Species Human
Accession P27797
Synonym cC1qR, CRT, HEL-S-99n, RO, SSA
Background Calreticulin is a multifunctional protein. It acts as a main Ca(2+)-binding (storage) protein in the lumen of the endoplasmic reticulum. Calreticulin binds Ca2+ ions (a second messenger in signal transduction), rendering it inactive. The Ca2+ is bound with low affinity, but high capacity, and can be released on a signal. Located in storage compartments associated with the endoplasmic reticulum, calreticulin also binds to misfolded proteins and prevents them from being exported from the endoplasmic reticulum to the golgi apparatus. 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 reduces the binding of androgen receptor to its hormone-responsive DNA element and inhibits androgen receptor and retinoic acid receptor transcriptional activities in vivo, as well as retinoic acid-induced neuronal differentiation. Therefore, calreticulin acts as a significant modulator of the regulation of gene transcription by nuclear hormone receptors.
Description A DNA sequence encoding the human CALR (P27797) (Met1-Ala413) was expressed with the Fc region of human IgG1 at the C-terminus.
Source HEK293
Predicted N Terminal Glu 18
AA Sequence Met1-Ala413
Molecular Weight The recombinant human CALR/Fc is a disulfide-linked homodimer. The reduced monomer comprises 637 a.a. and has a predicted molecular mass of 73 kDa. The apparent molecular mass of the protein is approximately 96 and 38 kDa in SDS-PAGE under reducing conditions.
Purity (75.9+20.5)% as determined by SDS-PAGE
Endotoxin < 1.0 EU per μg of the protein as determined by the LAL method
Bioactivity Please contact us for detailed information
Formulation Lyophilized from sterile PBS, pH 7.4.
Stability The recombinant proteins are stable for up to 1 year from date of receipt at -70°C.
Usage For Research Use Only
Storage Store the protein under sterile conditions at -20°C to -80°C. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.

Target Details

Target Function Calcium-binding chaperone that promotes folding, oligomeric assembly and quality control in the endoplasmic reticulum (ER) via the calreticulin/calnexin cycle. This lectin interacts transiently with almost all of the monoglucosylated glycoproteins that are synthesized in the ER. Interacts with the DNA-binding domain of NR3C1 and mediates its nuclear export. Involved in maternal gene expression regulation. May participate in oocyte maturation via the regulation of calcium homeostasis. Present in the cortical granules of non-activated oocytes, is exocytosed during the cortical reaction in response to oocyte activation and might participate in the block to polyspermy.
Subcellular Location Endoplasmic reticulum lumen. Cytoplasm, cytosol. Secreted, extracellular space, extracellular matrix. Cell surface. Sarcoplasmic reticulum lumen. Cytoplasmic vesicle, secretory vesicle, Cortical granule. Cytolytic granule.
Protein Families Calreticulin family
Database References

Gene Functions References

  1. unwanted cells such as aging neutrophils and living cancer cells are susceptible to "labeling" by secreted calreticulin (CRT) from macrophages, enabling their clearance through programmed cell removal. PMID: 30097573
  2. Patients with CALR mutation had significantly higher concentration of PDGF-BB and lower concentration of SDF-1alpha than patients with JAK2V617F mutation. High concentration of PDGF-BB and low concentration of SDF-1alpha in patients with CALR(+) ET may indicate a contribution of these chemokines in disturbed Ca2+ metabolism in platelets. PMID: 29390868
  3. These results implicate miR-455 regulated hydrogen sulfide protection of lung epithelial cells against hypoxia-induced apoptosis by stimulating Calr PMID: 30193773
  4. Calreticulin has a dual nature, and it has been found to be up-regulated or down-regulated in several types of cancer serving as either oncogene or anti-oncogene. PMID: 30444198
  5. Study propose that leukocytes infiltration via the binding of CRT to ITGAs is necessary for the onset and development of the ulcerative colitis and the inhibition of this interaction may be a novel therapeutic strategy for the treatment of inflammatory bowel diseases. PMID: 29773794
  6. Triplex probe-based TaqMan qPCR is an accurate and sensitive method for screening essential thrombocythemia or primary myelofibrosis patients with type I and II mutations in CALR. PMID: 30080988
  7. Comprehensive genomic characterization identified distinct genetic subgroups and provided a classification of myeloproliferative neoplasms on the basis of causal biologic mechanisms. Mutations in JAK2, CALR, or MPL being the sole abnormality in 45% of the patients. PMID: 30304655
  8. The prevalence of CALR mutation in JAK2V617F-negative essential thrombocythemia in this study is 35.7%. HRM is an effective method of detecting CALR mutation and is a more advantageous method of screening for CALR mutation. PMID: 29521158
  9. MPL and CALR genotypes show a similar clinical picture at essential thrombocythaemia diagnosis. In CALR genotype features of prefibrotic myelofibrosis are common. PMID: 29934356
  10. explored CRT reactivity of 14 different recombinant monoclonal antibodies (mAbs) derived from CLL patients carrying BCRs from various different stereotyped subsets PMID: 28751563
  11. The novel mutations occurred and changed the amino acid sequence of the C domain amino acid residues of CALR, which will interfere with the calcium-binding capacity of the molecule. The CALR mutations will improve our understanding of the pathophysiology of myeloproliferative neoplasms. PMID: 28747287
  12. Our study shows that JAK2V617F leads to abnormal expression of numerous proteins at the membrane of circulating PV red blood cells, with overexpression of CALR and persistence of CANX PMID: 28385780
  13. In 94.9% of PV, 85.5% ET and 85.2% PMF, authors found mutations in JAK2, MPL or CALR. 74.9% carried JAK2V617F, 12.3% CALR mutations, 2.1% MPL mutations and 10.7% were triple negative. PMID: 28990497
  14. these data support the model that CALR-mutated essential thrombocythemia could be considered as a distinct disease entity from JAK2V617F-positive myeloproliferative neoplasms PMID: 29217833
  15. This phenotypic diversity is further emphasized by the following report of a patient with an isolated erythrocytosis, persistent for nearly twelve years, associated with a CALR exon 9 mutation PMID: 28711709
  16. CALR exon 9 mutation is associated with myeloproliferative neoplasms. PMID: 28411309
  17. Absence of CALR mutations in JAK2-negative polycythemia. PMID: 27758825
  18. In 136 patients with myelofibrosis and a median age of 58 years who underwent allogeneic stem cell transplantation (AHSCT) for molecular residual disease, the percentage of molecular clearance on day 100 was higher in CALR-mutated patients (92%) in comparison with MPL- (75%) and JAKV617F-mutated patients (67%). PMID: 28714945
  19. Mutational subtypes of CALR correlate with different clinical features in Japanese patients with myeloproliferative neoplasms. PMID: 29464483
  20. CALR mutations is associated with non-hepatosplenic extramedullary hematopoiesis(NHS-EMH) and may possibly contribute to the pathogenesis of primary myelofibrosis -associated NHS-EMH. PMID: 27315113
  21. This study demonstrated that two patients had a heterozygous CALR exon9 mutation locating outside the coding region and did not alter the amino acid sequence of this protein. PMID: 28625126
  22. Multivariate analysis adjusted for age, sex, follow-up period and hematological parameters confirmed that increased activated B cells were universally present in JAK2-mutated, CALR-mutated and triple-negative ET patients when compared to healthy adults. PMID: 28415571
  23. these results reveal proteome alterations in MPN granulocytes depending on the phenotype and genotype of patients, highlighting new oncogenic mechanisms associated with JAK2 mutations and overexpression of calreticulin PMID: 28314843
  24. CALR mutation is associated with Essential thrombocythemia. PMID: 28205126
  25. the CALR-mutant stem cell would achieve clonal dominance much faster than the JAK2-mutant one and confirm the model initially proposed in which the clonal evolution of CALR-mutant MPN appears to be mainly associated with a progressive expansion of a mutant heterozygous clone that eventually becomes fully dominant in the bone marrow. PMID: 28422716
  26. The present study detected expression of CRT in patients with osteosarcoma , in the non-metastasis group compared with the metastasis group, and in the chemotherapy group compared with the non-chemotherapy group. CONCLUSIONS: These results could indicate a brand-new biological marker which may be applied to estimate the features and prognosis of osteosarcoma. PMID: 28106543
  27. in molecularly annotated ET patients at diagnosis, JAK2-V617F patients have more circulating microparticles and higher MP-associated procoagulant activities than CALR-mutated and TN ET patients. PMID: 27247323
  28. results suggest that CALR exon 9 mutations hold promise as targets for cancer immune therapies; for example as targets for vaccines or adoptive cell therapies. In order to formally establish that the CALR mutations act as tumor antigens for immunotherapy, we are currently working to establish specific T-cell clones to show that such clones recognize target cells that endogenously express mutated CALR PMID: 27560107
  29. Report PCR clamping technique for detection of type 1 and type 2 mutations in CALR gene in myeloproliferative neoplasms. PMID: 28031530
  30. Late-stage inhibition of autophagy enhances calreticulin surface exposure in colonic tumor cells. PMID: 27825129
  31. JAK2 and CALR mutations have roles in patients with essential thrombocythemia PMID: 27486987
  32. Clinical features of JAK2V617F- or CALR-mutated essential thrombocythemia and primary myelofibrosis. PMID: 26994960
  33. Studies indicate there are two main types of calreticulin gene (CALR) mutants, type 1 and type 2, and there is evidence about their distinct clinical/prognostic implications. PMID: 27384487
  34. our data suggest the involvement of autoimmune reactivity to CRT in a subset of patients suffering from DCM or HCM. PMID: 27689957
  35. Endoplasmic reticulum chaperone CRT plays a regulatory role in the invasion of EVTs, suggesting the importance of CRT expression in placental development during early pregnancy. PMID: 28938427
  36. findings demonstrate the potency of CALR mutants to drive expression of megakaryocytic differentiation markers such as NF-E2 and CD41 as well as Mpl. Furthermore, CALR mutants undergo accelerated protein degradation that involves the secretory pathway and/or protein glycosylation. PMID: 27177927
  37. Essential Thrombocythemia and Primary Myelofibrosis patients with CALR mutations are at high risk for Thrombotic Events. PMID: 28766534
  38. These findings showed that mutant CALR activates jak-stat signaling through an mpl-dependent mechanism to mediate pathogenic thrombopoiesis in zebrafish, and illustrated that the signaling machinery related to mutant CALR tumorigenesis are conserved between human and zebrafish. PMID: 27716741
  39. The present work suggests that Ca(2+)-dependent regulation is caused by different conformations of a long proline-rich loop that changes the accessibility to the peptide/lectin-binding site. Our results indicate that the binding of Ca(2+) to calreticulin may thus not only just be a question of Ca(2+) storage but is likely to have an impact on the chaperone activity. PMID: 27195812
  40. CRT regulates TGF-beta1-induced-EMT through modulating Smad signaling PMID: 28778674
  41. Our results showed that a wide range of different CALR mutations are associated with a distinct ET clinical phenotype that is associated with the male gender, younger age at diagnosis, higher platelet and lower leukocyte and erythrocyte counts and lower hemoglobin level, and a milder clinical course. PMID: 27521277
  42. alpha-Integrin expression and function modulates presentation of cell surface calreticulin. PMID: 27310876
  43. Although CALR mutations resulted in protein instability and proteosomal degradation, mutant CALR was able to enhance megakaryopoiesis and pro-platelet production from human CD34(+) progenitors. PMID: 27740635
  44. Studies show that all CALR mutations generate frameshift mutation in the exon 9, which encodes the C-terminus end conferring a common mutant-specific sequence in all mutants. Mutant CALR constitutively activates MPL to induce cellular transformation. The interaction between the mutant CALR and MPL is achieved by the conformational change in the C-terminal allowing N-domain binding to MPL. [review] PMID: 28741795
  45. C-CALR in response to Ca2+ undergoes conformational changes that trigger its function to export GR from the nucleus, resetting the stress response of normal erythroid cells. Impairment of this function in JAK2V617F-positive erythroid cells maintains EPO-R signaling in proliferation mode, contributing to erythrocytosis in PV. PMID: 28232234
  46. Mannan-binding lectin (MBL) bound to T cells through interaction between the collagen-like region of MBL and calreticulin (CRT) expressed on the T-cell surface. PMID: 28209773
  47. CRT exposure represents a novel powerful prognostic biomarker for patients with acute myeloid leukemia. PMID: 27802968
  48. In absence of CALR, immature MPO protein precursors are degraded in the proteasome. PMID: 27013444
  49. In patients with HD, a panel using calretinin and peripherin with or without MAP-2 may be most helpful in identifying transition zones PMID: 26469323
  50. Coexisting mutations of the JAK2, CALR, and MPL genes in myeloproliferative neoplasms suggest that CALR and MPL should be analyzed not only in JAK2-negative patients but also in low V617F mutation patients. PMID: 27855276


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Proteins are sensitive to heat, and freeze-drying can preserve the activity of the majority of proteins. It improves protein stability, extends storage time, and reduces shipping costs. However, freeze-drying can also lead to the loss of the active portion of the protein and cause aggregation and denaturation issues. Nonetheless, these adverse effects can be minimized by incorporating protective agents such as stabilizers, additives, and excipients, and by carefully controlling various lyophilization conditions.

Commonly used protectant include saccharides, polyols, polymers, surfactants, some proteins and amino acids etc. We usually add 8% (mass ratio by volume) of trehalose and mannitol as lyoprotectant. Trehalose can significantly prevent the alter of the protein secondary structure, the extension and aggregation of proteins during freeze-drying process; mannitol is also a universal applied protectant and fillers, which can reduce the aggregation of certain proteins after lyophilization.

Our protein products do not contain carrier protein or other additives (such as bovine serum albumin (BSA), human serum albumin (HSA) and sucrose, etc., and when lyophilized with the solution with the lowest salt content, they often cannot form A white grid structure, but a small amount of protein is deposited in the tube during the freeze-drying process, forming a thin or invisible transparent protein layer.

Reminder: Before opening the tube cap, we recommend that you quickly centrifuge for 20-30 seconds in a small centrifuge, so that the protein attached to the tube cap or the tube wall can be aggregated at the bottom of the tube. Our quality control procedures ensure that each tube contains the correct amount of protein, and although sometimes you can't see the protein powder, the amount of protein in the tube is still very precise.

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