Anti-Calreticulin, clone 4E23

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 (1). CRT is also known as CRP-55, calregulin and HACBP (high affinity calcium-binding protein) (1,2). 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 (aa189-288) 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 (1,3). The P-domain may interact with the cochaperone ERp57 (Grp58), a thiol reductase. 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 (3,4). Other functions atttributed to CRT include adhesion, blood function, cardiac and neuronal development gene expression and other diverse functions. CRT knockout mice indicate a role in heart development, it is required for embryonic heart development, but is only expresed at a low level in the mature heart. CRT is also implicated as an autoantigen in systemic lupus erythematosus, rheumatoid arthritis, celiac disease, complete congenital heart block and halothane hepatitis (1). Applications: Suitable for use in Immunoprecipitation, Western Blot and Immunohistochemistry. Other applications have not been tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.