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GENE AND PROTEIN SUMMARY

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Gene name

CALR

Description

calreticulin

Protein class

Candidate cancer biomarkers, Mapped to UniProt SWISS-PROT, Plasma proteins, Potential transmembrane proteins, Potentially secreted proteins

Protein evidence

High

Entrez gene summary

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]

External links

Ensembl, UniProt, Entrez gene, neXtProt, Antibodypedia

No of splice variants

5 in total
0 with predicted TM region
2 with predicted signal peptide

SUBCELLULAR LOCATION SUMMARY

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Pending subcellular analysis

NORMAL TISSUE & ORGAN SUMMARY

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Expression summary

Distinct expression in thyroid, weaker expression in other tissues.

Tissue specificity

Expressed in 46 out of 81 cell types

Reliability (APE)

Low

Antibodies in assay

CAB001513, HPA002242, CAB019952
 

Organ

No of cell types

Protein expression

CNS (brain) 11
Hematopoietic (blood) 8
Liver and pancreas 5
Digestive (GI-tract) 13
Respiratory (lung) 4
Cardiovascular 1
Female tissues 12
Placenta 2
Male tissues 5
Urinary tract (kidney) 3
Skin and soft tissues 14
Endocrine tissues 3

Level of annotated protein expression





High
Medium
Low
None

CANCER TISSUE SUMMARY

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Staining summary

Antibody staining in 81% of the cancers

Antibodies in assay

CAB001513, HPA002242, CAB019952
 

Tissue

Cancer staining

Protein
expression of
normal tissue

Breast cancer
 
Carcinoid
 
Cervical cancer
 
 
Colorectal cancer
 
 
Endometrial cancer
 
 
Glioma
 
Head and neck cancer
 
 
Liver cancer
 
 
Lung cancer
 
 
Lymphoma
 
 
 

Tissue

Cancer staining

Protein
expression of
normal tissue

Melanoma
 
Ovarian cancer
 
Pancreatic cancer
 
Prostate cancer
 
Renal cancer
 
Skin cancer
 
Stomach cancer
 
 
Testis cancer
 
Thyroid cancer
 
Urothelial cancer
 

Level of antibody staining





Strong
Moderate
Weak
Negative

CELL LINE SUMMARY

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RNA evidence

High
 

Cell line

Cell origin

RNA abundance

IH staining

IF intensity

CAB001513

HPA002242

CAB019952

 

A-431 Skin High

-

A-549 Lung High

-

CACO-2 Colon High

-

HEK 293 Embryonal kidney High

-

HeLa Cervix High

-

Hep-G2 Liver High

-

MCF-7 Pleural effusion High

-

PC-3 Bone marrow High

-

RT-4 Urinary bladder High

-

U-2 OS Bone High

-

U-251 MG Brain High

-

ANTIBODY SUMMARY

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Antibody

Clonality

Validation

CAB001513 pAb
HPA002242 pAb
CAB019952 pAb