Calreticulin (UniProt P27797; also known as Calregulin, CRP55, CRT, Endoplasmic reticulum resident protein 60, ERp60, grp60, HACBP) is encoded by the CALR (also known as CRTC) gene (Gene ID 811) in human. Calreticulin (CRT), BiP (GRP78 or heat shock 70 kDa protein 5), and protein disulphide isomerase (PDI) are ER lumen folding factors that, together with other PTM enzymes, assist the process of newly synthesized proteins before their release from ER. CRT, BiP, and PDI themselves are subject to posttranslational signal peptide removal after their synthesis, exposing E18, E19, and D18 at the newly formed N-terminus, respectively. The N-terminus D and E residues of the mature proteins are permissive to arginine-tRNA-protein transferase 1/ATE1-catalyzed arginylation, forming arginylated mature proteins (R-CRT, R-BiP, R-PDI) with altered cellular localization to allow their participation in non-ER functions. Although only the basal levels of R-CRT and R-PDI, but not R-BiP, are generally detectible in non-stimulated cells, upregulated N-terminal arginylation of all three proteins is observed upon cytosolic dsDNA exposure and proteasomal inhibition, indicating a shared role in innate immune responses to invading microbes. In addition, ER stress induction by thapsigargin treatment synergistically boosts proteasomal inhibition-induced upregulation of cellular levels of R-CRT, R-BiP, and R-PDI, suggesting that ER stress accelerates the supply of ER lumenal CRT, BiP, and DPI for N-terminal arginylation.

This rabbit polyclonal antibody specifically detected the immunogen peptide, but not the control peptide without arginylation at the N-terminal Glu18 (Cha-Molstad, H., et al. (2015). Nat. Cell Biol. 17(7):917-929).

Epitope: N-terminus

Linear peptide corresponding to the N-terminal sequence of arginylated mature human Calreticulin.

Detect arginylated mature calreticulin using this rabbit polyclonal Anti-Calreticulin, arginylated (Nt-Glu18), Cat. No. ABS1671, validated for use in ELISA, Immunocytochemistry, and Western Blotting.

Immunocytochemistry Analysis: A 1:100 dilution from a representative lot detected Calreticulin Nt-Glu18 arginylation induction in (18-hr 3 µM MG132 and 200 nM thapsigargin) treated HeLa cells (Courtesy of Yong Tae Kwon, Ph.D. , Seoul National University, Korea).

Western Blotting Analysis: 0.2 µg/mL from a representative lot detected Calreticulin Nt-Glu18 arginylation induction in (18-hr 3 µM MG132 and 200 nM thapsigargin) treated HeLa cells (Courtesy of Yong Tae Kwon, Ph.D. , Seoul National University, Korea).

ELISA Analysis: A representative lot detected the immunogen peptide, but not the control peptide without arginylation at the N-terminal Glu18 (Cha-Molstad, H., et al. (2015). Nat. Cell Biol. 17(7):917-929).

Western Blotting Analysis: A representative lot detected Calreticulin Nt-Glu18 arginylation induction upon arginine-tRNA-protein transferase 1 (ATE1) 1A7A isoform overexpression or transfection of various dsDNAs, including poly(dA:dT), in HeLa cells. Combined proteasome inhibition and ER stress induction by an 18-hr 10 µM MG132 and 100 nM thapsigargin treatment synergized the two drugs′ efficacy toward cellular Calreticulin Nt-Glu18 arginylation induction (Cha-Molstad, H., et al. (2015). Nat. Cell Biol. 17(7):917-929).

Research Category
Signaling

Evaluated by Western Blotting in HEK293 cell lysate.

Western Blotting Analysis: 1 µg/mL of this antibody detected Calreticulin Nt-Glu18 arginylation induction in 7.5 µg of lysate from (17-hr 3 µM MG132 and 200 nM thapsigargin) treated HEK293 cells.

~55 kDa observed. 46.6 kDa calculated. Uncharacterized bands may be observed in some lysate(s).

Affinity purified.

Purified rabbit polyclonal antibody in buffer containing PBS with 0.05% sodium azide.

Stable for 1 year at 2-8°C from date of receipt.

Concentration: Please refer to lot specific datasheet.

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