Tbio CALR Calreticulin

Protein Summary

Description

Calcium-binding chaperone that promotes folding, oligomeric assembly and quality control in the endoplasmic reticulum (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 and mediates its nuclear export. Involved in maternal gene expression regulation. May participate in oocyte maturation via the regulation of calcium homeostasis (By similarity). Calreticulin is a multifunctional protein that acts as a major Ca(2+)-binding (storage) protein in the lumen of the endoplasmic reticulum. It is also found in the nucleus, suggesting that it may have a role in transcription regulation. Calreticulin binds to the synthetic peptide KLGFFKR, which is almost identical to an amino acid sequence in the DNA-binding domain of the superfamily of nuclear receptors. Calreticulin binds to antibodies in certain sera of systemic lupus and Sjogren patients which contain anti-Ro/SSA antibodies, it is highly conserved among species, and it is located in the endoplasmic and sarcoplasmic reticulum where it may bind calcium. The amino terminus of calreticulin interacts with the DNA-binding domain of the glucocorticoid receptor and prevents the receptor from binding to its specific glucocorticoid response element. Calreticulin can inhibit the binding of androgen receptor to its hormone-responsive DNA element and can inhibit androgen receptor and retinoic acid receptor transcriptional activities in vivo, as well as retinoic acid-induced neuronal differentiation. Thus, calreticulin can act as an important modulator of the regulation of gene transcription by nuclear hormone receptors. Systemic lupus erythematosus is associated with increased autoantibody titers against calreticulin but calreticulin is not a Ro/SS-A antigen. Earlier papers referred to calreticulin as an Ro/SS-A antigen but this was later disproven. Increased autoantibody titer against human calreticulin is found in infants with complete congenital heart block of both the IgG and IgM classes. [provided by RefSeq, Jul 2008]

Uniprot Accession IDs

• P27797
• Q6IAT4
• Q9UDG2

Gene Name

• CALR

Ensembl ID

• ENST00000316448
• ENSP00000320866
• ENSG00000179218

Symbol

• CRTC
• RO
• CRT
• SSA
• cC1qR
• HEL-S-99n

Knowledge Table

Most Knowledge About	Knowledge Value (0 to 1 scale)
biological process	1
interacting protein	1
molecular function	0.99
biological term	0.98
transcription factor binding site profile	0.93

Protein Classes

PANTHER Classes

Protein / Calcium-binding Protein / Calreticulin

DTO Classes

Protein / Calcium-binding Protein / Calreticulin

IDG Development Level Summary

Tdark

These are targets about which virtually nothing is known. They do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 2465.3   (req: < 5)

Gene RIFs: 420   (req: <= 3)

Antibodies: 991   (req: <= 50)

Tbio

These targets do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 2465.3   (req: >= 5)

Gene RIFs: 420   (req: > 3)

Antibodies: 991   (req: > 50)

- OR - satisfy the following criterion:

Gene Ontology Terms: 59

Tchem

Target has at least one ChEMBL compound with an activity cutoff of < 30 nM - AND - satisfies the preceding conditions

Active Ligand: 0

Tclin

Target has at least one approved drug - AND - satisfies the preceding conditions

Active Drug: 0