|PROSITE documentation PDOC00636 [for PROSITE entry PS00804]|
Calreticulin  (also known as calregulin, CRP55 or HACBP) is a high-capacity calcium-binding protein which is present in most tissues and located at the periphery of the endoplasmic (ER) and the sarcoplamic reticulum (SR) membranes. It probably plays a role in the storage of calcium in the lumen of the ER and SR and it may well have other important functions. Structurally, calreticulin is a protein of about 400 amino acid residues consisting of three domains:
a) An N-terminal, probably globular, domain of about 180 amino acid residues (N-domain); b) A central domain of about 70 residues (P-domain) which contains three repeats of an acidic 17 amino acid motif. This region binds calcium with a low-capacity, but a high-affinity; c) A C-terminal domain rich in acidic residues and in lysine (C-domain). This region binds calcium with a high-capacity but a low-affinity.
Calreticulin is evolutionary related to the following proteins:
We developed three signature patterns for this family of proteins. The first two patterns are based on conserved regions in the N-domain; the third pattern corresponds to positions 4 to 16 of the repeated motif in the P-domain.Last update:
December 2004 / Pattern and text revised.
PROSITE methods (with tools and information) covered by this documentation:
|1||Authors||Michalak M., Milner R.E., Burns K., Opas M.|
|Source||Biochem. J. 285:681-692(1992).|
|2||Authors||Bergeron J.J.M., Brenner M.B., Thomas D.Y., Williams D.B.|
|Title||Calnexin: a membrane-bound chaperone of the endoplasmic reticulum.|
|Source||Trends Biochem. Sci. 19:124-128(1994).|
|3||Authors||Watanabe D., Yamada K., Nishina Y., Tajima Y., Koshimizu U., Nagata A., Nishimune Y.|
|Title||Molecular cloning of a novel Ca(2+)-binding protein (calmegin) specifically expressed during male meiotic germ cell development.|
|Source||J. Biol. Chem. 269:7744-7749(1994).|