PS00805

Calreticulin family repeated motif signature

PROSITE patterns entry
Member databasePROSITE patterns
PROSITE patterns typeconserved site
Short nameCALRETICULIN_REPEAT

Description

Calreticulin
[2]
(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: - Onchocerca volvulus antigen RAL-1. RAL-1 is highly similar to calreticulin, but possesses a C-terminal domain rich in lysine and arginine and lacks acidic residues and is therefore not expected to bind calcium in that region. - Calnexin
[3]
. A calcium-binding protein that interacts with newly synthesized glycoproteins in the endoplasmic reticulum. It seems to play a major role in the quality control apparatus of the ER by the retention of incorrectly folded proteins. - Calmegin
[1]
(or calnexin-T), a testis-specific calcium-binding protein highly similar to calnexin. 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.

References

1.Molecular cloning of a novel Ca(2+)-binding protein (calmegin) specifically expressed during male meiotic germ cell development. Watanabe D, Yamada K, Nishina Y, Tajima Y, Koshimizu U, Nagata A, Nishimune Y. J. Biol. Chem. 269, 7744-9, (1994). View articlePMID: 8126001

2.Calreticulin. Michalak M, Milner RE, Burns K, Opas M. Biochem. J. 285 ( Pt 3), 681-92, (1992). View articlePMID: 1497605

3.Calnexin: a membrane-bound chaperone of the endoplasmic reticulum. Bergeron JJ, Brenner MB, Thomas DY, Williams DB. Trends Biochem. Sci. 19, 124-8, (1994). View articlePMID: 8203019

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