The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

calr  -  calreticulin

Xenopus (Silurana) tropicalis

Synonyms: cc1qr, crc, crt, ssa
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

High impact information on calr

  • We examined the role of the luminal Ca(2+)-binding protein calreticulin (CRT) in IP3-mediated Ca2+ signaling by using Ca2+ wave activity as a sensitive Ca2+ release assay [1].
  • Deletion mutagenesis demonstrated that CRT inhibition was mediated by the high affinity-low capacity Ca(2+)-binding domain, which contributes little to Ca2+ storage [1].
  • This novel function of CRT in intracellular Ca2+ signaling may be regulated by Ca2+ occupancy of the high affinity binding site [1].
  • In Xenopus laevis oocytes, overexpression of calreticulin suppresses inositol 1,4,5-trisphosphate-induced Ca2+ oscillations in a manner consistent with inhibition of Ca2+ uptake into the endoplasmic reticulum [2].
  • Calreticulin belongs to a novel class of lectin ER chaperones that modulate immature protein folding [2].

Biological context of calr

  • Strong expression of the calreticulin gene in the liver of Rana rugosa tadpoles, but not adult frogs [3].
  • These results suggest that the expression of the CLT gene is tissue-dependent in the frog, R. rugosa, and that CLT probably functions biochemically in liver cells even when its gene expression is low [3].
  • Using rat CLT cDNA as a probe, a 2.4-kilobase frog cDNA clone was isolated from a frog liver cDNA library [3].

Anatomical context of calr

  • Here we report that the alternatively spliced isoforms of the sarcoendoplasmic reticulum Ca2+-ATPase (SERCA)2 gene display differential Ca2+ wave properties and sensitivity to modulation by calreticulin [2].
  • Calreticulin (CRT) is a highly conserved Ca(2+)-binding protein that resides in the lumen of the endoplasmic reticulum (ER) [4].
  • Identification of calreticulin isoforms in the central nervous system [5].
  • Immunostaining showed that CLT was distributed in the cytoplasm of liver cells [3].

Associations of calr with chemical compounds

  • Overexpression of CRT inhibited repetitive IP3-induced Ca2+ waves [1].
  • The cDNA encoded 419 amino acids including an 18-residue NH2-terminal signal sequence that was 76% homologous to the rat CLT sequence and was 84% homologous to the partial sequence of Xenopus laevis CLT (Treves et al. [1992] Biochem. J. 287:579-581) [3].

Analytical, diagnostic and therapeutic context of calr

  • We demonstrate by glucosidase inhibition and site-directed mutagenesis that a putative glycosylated residue (N1036) in SERCA2b is critical in determining both the selective targeting of calreticulin to SERCA2b and isoform functional differences [2].
  • Furthermore, CLT was recognized by Western blot analysis of total proteins in the liver of adult frogs [3].
  • CLT with M(r) = 52 kDa, estimated by SDS-PAGE, was purified from frog livers [3].
  • Northern blot analysis indicated that the CLT mRNA level was very high in the liver of tadpoles, but extremely low in adult frogs [3].


  1. Calreticulin inhibits repetitive intracellular Ca2+ waves. Camacho, P., Lechleiter, J.D. Cell (1995) [Pubmed]
  2. Differential modulation of SERCA2 isoforms by calreticulin. John, L.M., Lechleiter, J.D., Camacho, P. J. Cell Biol. (1998) [Pubmed]
  3. Strong expression of the calreticulin gene in the liver of Rana rugosa tadpoles, but not adult frogs. Yamamoto, S., Kondo, Y., Hanada, H., Nakamura, M. J. Exp. Zool. (1996) [Pubmed]
  4. Calreticulin modulates capacitative Ca2+ influx by controlling the extent of inositol 1,4,5-trisphosphate-induced Ca2+ store depletion. Xu, W., Longo, F.J., Wintermantel, M.R., Jiang, X., Clark, R.A., DeLisle, S. J. Biol. Chem. (2000) [Pubmed]
  5. Identification of calreticulin isoforms in the central nervous system. Treves, S., Zorzato, F., Pozzan, T. Biochem. J. (1992) [Pubmed]
WikiGenes - Universities