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calreticulin; CRP55; calregulin; HACBP; ERp60; grp60 (CALR, CRTC)

Function: - molecular Ca+2 binding chaperone promoting folding, oligomeric assembly & quality control in the ER via the calreticulin/calnexin cycle - this lectin interacts transiently with almost all of the monoglucosylated glycoproteins that are synthesized in the ER - interacts with the DNA-binding domain of NR3C1 & mediates its nuclear export monomer - component of an EIF2 complex at least composed of CUGBP1, CALR, CALR3, EIF2S1, EIF2S2, HSP90B1 & HSPA5 - interacts with PDIA3/ERp57 & with NR3C1 (putative) Structure: - can be divided into a N-terminal globular domain, a proline-rich P-domain forming an elongated arm-like structure & a C-terminal acidic domain - the P-domain binds one molecule of Ca+2 with high affinity; the acidic C-domain binds multiple Ca+2 with low affinity - the interaction with glycans occurs through a binding site in the globular lectin domain - the Zn+2 binding sites are localized to the N-domain - associates with PDIA3 through the tip of the extended arm formed by the P-domain - belongs to the calreticulin family - molecular weight by mass spec: mass=46879 [8] Compartment: - endoplasmic reticulum lumen, cytoplasm, secreted - extracellular space, extracellular matrix - cell surface - found on cell surface (T cells), cytosol & extracellular matrix - associated with the lytic granules in cytolytic T-cells Pathology: - CALR gene mutation may be associated with - essential thrombocythemia - myelofibrosis Note: - originally thought to be the 52 kD Ro autoantigen [7]

Interactions

molecular events

Related

CALR (calreticulin) gene exon 9 mutation calreticulin (CALR) gene mutation calreticulin-3 (calreticulin-2, CALR3, CRT2)

General

nuclear protein

Properties

SIZE: entity length = 417 aa MW = 48 kD COMPARTMENT: cytoplasm endoplasmic reticulum MOTIF: signal sequence {1-17} N {18-197} MOTIF: cysteine residue {C105} MODIFICATION: cysteine residue {C137} cysteine residue {C137} MODIFICATION: cysteine residue {C105} repeat-1.1 {191-202} P {198-308} MOTIF: repeat-1.2 {210-221} repeat-1.2 {227-238} repeat-1.4 {244-255} repeat-2.1 {259-269} repeat-2.2 {273-283} repeat-2.3 {287-297} C {309-417} MOTIF: N-glycosylation site {N344} lysine-rich region {351-408} MOTIF: lysine residue (SEVERAL) peptide motif {414-417}

References

  1. UniProt :accession P27797
  2. Wikipedia; Note: calreticulin entry http://en.wikipedia.org/wiki/calreticulin
  3. Functional glycomics gateway - glycan binding Note: calreticulin http://www.functionalglycomics.org/glycomics/GBPServlet?&operationtype=view&cbpId=cbp_hum_other_405
  4. Burns K et al Modulation of gene expression by calreticulin binding to glucocorticoid receptor. Nature 367:476 1994 PMID: 8107808
  5. Dedhar et al Inhibition of nuclear hormone receptor activity by calreticulin. Nature 367:480 1994 PMID: 8107809
  6. Entrez Gene :accession 811
  7. McCauliffe DP Molecular cloning, expression, and chromosome 19 localization of a human Ro/SS-A autoantigen. J Clin Invest. 1990 May;85(5):1379-91 PMID: 2332496
  8. Holaska JM et al Calreticulin Is a receptor for nuclear export. J Cell Biol. 2001 Jan 8;152(1):127-40. PMID: 11149926

Component-of

molecular complex

Databases & Figures

OMIM 109091 UniProt P27797 Pfam PF00262 Entrez Gene 811 Kegg hsa:811 Contents of Cytotoxic T-cell Granules