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Not to be confused with calreticulin.
Calbindin 2
Symbols CALB2 ; CAB29; CAL2; CR
External IDs OMIM114051 MGI101914 HomoloGene1318 GeneCards: CALB2 Gene
Species Human Mouse
Entrez 794 12308
Ensembl ENSG00000172137 ENSMUSG00000003657
UniProt P22676 Q08331
RefSeq (mRNA) NM_001740 NM_007586
RefSeq (protein) NP_001731 NP_031612
Location (UCSC) Chr 16:
71.36 – 71.39 Mb
Chr 8:
110.14 – 110.17 Mb
PubMed search [1] [2]
Micrograph of a malignant epithelioid mesothelioma stained with an antibody against calretinin.

Calretinin also known as 29 kDa calbindin is a vitamin D-dependent calcium-binding protein involved in calcium signaling. In humans, the calretinin protein is encoded by the CALB2 gene.[1][2]


This gene encodes an intracellular calcium-binding protein belonging to the troponin C superfamily. Members of this protein family have six EF-hand domains which bind calcium. This protein plays a role in diverse cellular functions, including message targeting and intracellular calcium buffering. It also functions as a modulator of neuronal excitability[1]

Calretinin is abundantly expressed in neurons and in hair follicles.[3]

Clinical significance[edit]

Calretinin is a diagnostic marker for some human diseases, including Hirschsprung disease and some cancers.


Using immunohistochemistry, calretinin can be demonstrated in both benign mesothelium and in malignant mesothelioma[4] and can be used to help differentiate different lung tumours.[5] Antibodies to calretinin can also be used to distinguish between different types of brain tumour, demonstrating only those with neuronal rather than glial, differentiation.[6]

Hirschsprung disease[edit]

In Hirschsprung disease, calretinin IHC offers additional diagnostic value in specimens with inadequate amount of submucosa and rarely seen ganglion cells. The presence of ganglion cells consistently correlated with calretinin-positive thin nerve fibrils in the lamina propria, muscularis mucosae and superficial submucosa. These calretinin-positive thin nerve fibrils are absent in the aganglionic segments of bowel and in the areas without ganglion cells from the junction of normal with diseased rectum. Calretinin is strongly expressed in the submucosal and subserosal nerve trunks in the ganglionic segment. No calretinin expression is seen in the nerve trunks in the rest of the aganglionic segment. It has faint expression in the thick nerve trunks from the areas without ganglion cells. Faint positivity of the thick submucosal and subserosal nerves in the absence of ganglion cells and calretinin positive nerve fibrils, is characteristic of the junction of the aganglionic-to-normal rectum. [7]


  1. ^ a b "Entrez Gene: calbindin 2". 
  2. ^ Parmentier M, Passage E, Vassart G, Mattei MG (1991). "The human calbindin D28k (CALB1) and calretinin (CALB2) genes are located at 8q21.3----q22.1 and 16q22----q23, respectively, suggesting a common duplication with the carbonic anhydrase isozyme loci". Cytogenet. Cell Genet. 57 (1): 41–3. doi:10.1159/000133111. PMID 1906795. 
  3. ^ Poblet E, Jimenez F, de Cabo C, Prieto-Martin A, Sánchez-Prieto R (June 2005). "The calcium-binding protein calretinin is a marker of the companion cell layer of the human hair follicle". Br. J. Dermatol. 152 (6): 1316–20. doi:10.1111/j.1365-2133.2005.06603.x. PMID 15948999. 
  4. ^ Saydan N, Salicio V, Cappelli-Gotzos B, Gotzos V (2001). "Expression of calretinin in human mesothelioma cell lines and cell cycle analysis by flow cytometry". Anticancer Res. 21 (1A): 181–8. PMID 11299732. 
  5. ^ Marchevsky AM (March 2008). "Application of immunohistochemistry to the diagnosis of malignant mesothelioma". Arch. Pathol. Lab. Med. 132 (3): 397–401. doi:10.1043/1543-2165(2008)132[397:AOITTD]2.0.CO;2. PMID 18318582. 
  6. ^ Leong, Anthony S-Y; Cooper, Kumarason; Leong, F Joel W-M (2003). Manual of Diagnostic Cytology (2 ed.). Greenwich Medical Media, Ltd. pp. 45–46. ISBN 1-84110-100-1. 
  7. ^ Alexandrescu, S; Rosenberg, H; Tatevian, N (2013). "Role of calretinin immunohistochemical stain in evaluation of Hirschsprung disease: An institutional experience". International journal of clinical and experimental pathology 6 (12): 2955–61. PMC 3843278. PMID 24294384.  edit

Further reading[edit]

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.