CALR
GeneName
CALR
Summary
CALR, also known as calreticulin or Crt, is a 48 kDa multifunctional protein predominantly located in the endoplasmic reticulum, but also found in various cellular compartments including the cytoplasm, cell surface, and extracellular space. It plays a crucial role in calcium ion homeostasis, protein folding, and quality control within the endoplasmic reticulum. CALR is involved in several biological processes such as cardiac muscle cell differentiation, cellular responses to stimuli, and the regulation of gene expression. It also participates in immune responses by aiding in peptide antigen assembly with MHC class I molecules, and is implicated in processes like phagocytosis and cell migration.
Importance
CALR is relevant to: - Immune regulation and antigen presentation due to its role in MHC class I peptide loading - Cardiovascular research through its involvement in cardiac muscle cell differentiation - Cancer biology as it is associated with cellular responses to stress and apoptosis - Neurobiology, particularly in the context of neuronal differentiation and synaptic function - Disorders related to protein misfolding and endoplasmic reticulum stress, highlighting its role in protein quality control
Top Products
For researchers investigating CALR, we recommend two excellent primary antibodies that cater to a variety of applications. The first is the well-cited polyclonal antibody, Anti-Calreticulin antibody - ER Marker (ab2907), which has garnered 292 citations, highlighting its reliability in Western blotting (WB) and immunocytochemistry (ICC). In addition, we offer the recombinant antibody, Anti-Calreticulin antibody [EPR3924] - ER Marker (ab92516). This product is validated in knockout models and is suitable for a broader range of applications, including WB, ICC, flow cytometry (FC), and immunohistochemistry (IHC). With 173 citations, it demonstrates a solid presence in the research community. The recombinant nature of this antibody ensures batch-to-batch consistency, making it an excellent choice for researchers seeking dependable CALR detection.
Abcam Product Citation Summary
The data indicates a significant focus on the use of CALR antibodies in various human cell lines and models, particularly in the context of cancer research, including studies on acute lung injury, hepatic cells, and breast cancer. The applications primarily involve Western blotting, with some instances of immunocytochemistry and flow cytometry, highlighting the versatility of CALR as a target in different experimental setups.
Abcam Product Citation Table
Domain
Can be divided into a N-terminal globular domain, a proline-rich P-domain forming an elongated arm-like structure and a C-terminal acidic domain. The P-domain binds one molecule of calcium with high affinity, whereas the acidic C-domain binds multiple calcium ions with low affinity.
The interaction with glycans occurs through a binding site in the globular lectin domain.
The zinc binding sites are localized to the N-domain.
Associates with PDIA3 through the tip of the extended arm formed by the P-domain.
Function
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 (PubMed:7876246). Interacts with the DNA-binding domain of NR3C1 and mediates its nuclear export (PubMed:11149926). Involved in maternal gene expression regulation. May participate in oocyte maturation via the regulation of calcium homeostasis (By similarity). Present in the cortical granules of non-activated oocytes, is exocytosed during the cortical reaction in response to oocyte activation and might participate in the block to polyspermy (By similarity).
Involvement in disease
CALR somatic mutations are frequently found in myeloproliferative neoplasms lacking JAK2 or MPL mutations. Myeloproliferative neoplasms are chronic myeloid cancers characterized by overproduction of mature blood cells, and may evolve into acute myeloid leukemia. In addition to chronic myeloid leukemia with the BCR-ABL fusion gene, the three most common myeloproliferative neoplasms are essential thrombocythemia, polycythemia vera, and myelofibrosis.
Sequence Similarities
Belongs to the calreticulin family.
Cellular localization
- Endoplasmic reticulum lumen
- Cytoplasm
- Cytosol
- Secreted
- Extracellular space
- Extracellular matrix
- Cell surface
- Sarcoplasmic reticulum lumen
- Cytoplasmic vesicle
- Secretory vesicle
- Cortical granule
- Cytolytic granule
- Also found in cell surface (T cells), cytosol and extracellular matrix (PubMed:10358038). During oocyte maturation and after parthenogenetic activation accumulates in cortical granules. In pronuclear and early cleaved embryos localizes weakly to cytoplasm around nucleus and more strongly in the region near the cortex (By similarity). In cortical granules of non-activated oocytes, is exocytosed during the cortical reaction in response to oocyte activation (By similarity).
Alternative names
CRTC, CALR, Calreticulin, CRP55, Calregulin, Endoplasmic reticulum resident protein 60, HACBP, grp60, ERp60