Anti-Calreticulin precursor

Anti-Calreticulin precursor was affinity purified from monospecific antiserum by immunoaffinity chromatography. A BLAST analysis was used to suggest cross-reactivity with human, mouse, rat, primate, and chicken based on 100% sequence homology. Cross-reactivity with Calreticulin precursor from other sources has not been determined. Calreticulin is the major calcium binding protein found in smooth muscle sarcoplasmic reticulum (SR) and non-muscle endoplasmic reticulum (ER) membranes. This protein was originally identified in SR membranes and plays a minor role in calcium storage in skeletal and cardiac muscle SR. Calreticulin is also known as calregulin, CRP55, CaBP3, calsequestrin-like protein and Ro/SS-A antigen. Calreticulin binds calcium with low affinity and high capacity, however it also exhibits a single high affinity binding site. The highly conserved sequence Lys-Asp-Glu-Leu (KDEL) is present at the C-terminus of calreticulin and other resident ER proteins including glucose regulated protein 78 (GRP78), GRP94 and protein disulfide isomerase (PDI). This sequence is responsible for the retention of newly synthesized proteins within the ER lumen. This retention is reported to be mediated by a KDEL receptor. Recent reports indicate that calreticulin can act as a modulator of the regulation of gene transcription by nuclear hormone receptors and may also act as a molecular chaperone.