Technical Data
Calreticulin (CALR, SSA, Sicca Syndrome Antigen A, Ro, Autoantigen Ro)
Calreticulin (CRT) is a multifunctional, multi-compartmental protein most abundant in the ER lumen, but also found in other membrane-bound organelles, the cell surface and extracellularly. Reports of nuclear localization are likely immunostaining artifacts (7). CRT is also known as CRP-55, calregulin and HACBP (high affinity calcium-binding protein) (7,8). It contains the ER-retrieval sequence, KDEL, and has been best characterized as a soluble molecular chaperone of new or misfolded proteins and a Ca2+-binding protein. CRT is comprised of three domains; a 180 residue N-terminal domain, a proline-rich P-domain (residues 189288) that binds Ca2+ with high affininty and has homology with calnexin (CNX) and calmegin, and a 110 residue C-terminal domain that binds Ca2+ with low affinity but high capacity (7,9). The P-domain may interact with the cochaperone ERp57 (Grp58), a thiol reductase. The NMR structure of the P-domain (residues 189288) is an extended hairpin that seems to form an extended, somewhat curved protrusion from the CRT core domain (9). Both CRT and its membrane bound homolog, CNX, interact with proteins and glycoproteins that have monoglucosylated N-glycans (7,9,10). The CRT/CNX cycle promotes correct folding, inhibits aggregation of folding intermediates, blocks premature oligimerization, regulates ER degradation and provides quality control by preventing incompletely folded glycoproteins from exiting to the Golgi complex (9,10). Other functions atttributed to CRT include adhesion, blood function, cardiac and neuronal development gene expression and other diverse functions. CRT is also implicated as an autoantigen in systemic lupus erythematosus, rheumatoid arthritis, celiac disease, complete congenital heart block and halothane hepatitis (7).

Suitable for use in Western Blot. Other applications not tested.

Recommended Dilution:
Western Blot: 1:500

Positive Controls:
HeLa Cell Lysate

Storage and Stability:
May be stored at 4C for short-term only. For long-term storage, store at -20C. Aliquots are stable for at least 12 months at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
PabIgGAffinity Purified
50ul4C (-20C Glycerol)Blue IceHumanRabbit
Not determined
Synthetic 13aa peptide sequence (aa405-417) from human calreticulin with a cysteine residue added (KLH coupled).
Purified by Protein A affinity chromatography
Supplied as a liquid in PBS, pH 7.2, 0.09% azide, 50% glycerol
Recognizes human Calreticulin at ~63kD. Species Crossreactivity: mouse and rat.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.
1. Wada, I., Kai, M., Imai, S., Sakane, F., Kanoh, H. (1997) EMBO J. 16: 5420-5432. 2. Janicki, S., Monteiro, M.J., (1997) J. Cell Biol. 139: 485-495. 3. Lucero, H.A., Lebeche, D., Kaminer, B. (1998) J. Biol. Chem. 273: 9857-9863. 4. Tanaka, S., Uehara, T. and Nomura, Y. (2000) J. Biol. Chem. 275: 10388-10393. 5. Yoon, G.-S., et al. (2000) Cancer Rsch. 60: 1117-1120. 6. Laguerre, D.B., et al. (1998) J. Vir. 72 (6): 4940-4949. 7. Johnson, S. et al (2001) Trends Cell Biol 11(3): 122-129. 8. Smith, M.J. and Koch, G.L.E. (1989) EMBO J. 8 (12): 3581-3586. 9. Ellgaard, L., Helenius, A. (2001) Curr Opin Cell Biol 13(4): 431-437. 10. Helenuis, A., Aebi, M. (2001) Science 291: 2364-2369. 11. Antoniou, A.N.; Ford, S.; Pilley, E.S.; Blake, N.; Powis, S.J.; (2002) Immunology 106(2): 182-189.