Biology:CBR1

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Short description: Protein-coding gene in the species Homo sapiens


A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example

Carbonyl reductase 1, also known as CBR1, is an enzyme which in humans is encoded by the CBR1 gene.[1][2][3] The protein encoded by this gene belongs to the short-chain dehydrogenases/reductases (SDR) family, which function as NADPH-dependent oxidoreductases having wide specificity for carbonyl compounds, such as quinones, prostaglandins, and various xenobiotics. Alternatively spliced transcript variants have been found for this gene.[1]

Function

Carbonyl reductase is one of several monomeric, NADPH-dependent oxidoreductases having wide specificity for carbonyl compounds. This enzyme is widely distributed in human tissues. Another carbonyl reductase gene, CBR3, lies close to this gene on chromosome 21q22.12.[1] CBR1 metabolizes many toxic environmental quinones and pharmacological relevant substrates such as the anticancer doxorubicin.[4] Several studies have shown that CBR1 plays a protective role in oxidative stress, neurodegeneration, and apoptosis.[5] In addition, CBR1 inactivates lipid aldehydes during oxidative stress in cells. Therefore, CBR1 may play a beneficial role in protecting against cellular damage resulting from oxidative stress.[6]

Polymorphisms

Up-to-date two non-synonymous polymorphisms on CBR1 have been identified. The CBR1 V88I polymorphism encodes for a valine-to-isoleucine substitution at position 88 of the aminoacid chain. In vitro studies with recombinant proteins indicate that the CBR1 V88 isoform has a higher Vmax towards the substrates menadione (vitamin K3) and daunorubicin.[7] Recent studies in human liver cytosols show that an untranslated polymorphism on the 3'UTR region of the CBR1 gene (rs9024)[8] is associated with higher levels of the cardiotoxic metabolite doxorubicinol.[9]

Structure

Gene

Human CBR1 gene includes 8 exons.[1]

Protein

The enzyme consists of 277 amino acid residues and is widely distributed in human tissues such as liver, epidermis, stomach, small intestine, kidney, neuronal cells, and smooth muscle fibers.[10] The best substrates of CBR1 are quinones, including ubiquinone-1 and tocopherolquinone (vitamin E). Ubiquinones (coenzyme Q) are constitutive parts of the respiratory chain, and tocopherolquinone protects lipids of biological membranes against lipid peroxidation, indicating that CBR1 may play an important role as an oxidation–reduction catalyst in biological processes.[11]

Clinical significance

CBR1 has been reported to relate to tumor progression.[12] Suppression of CBR1 expression was associated with poor prognosis in uterine endometrial cancer and uterine cervical squamous cell carcinoma.[12] Previous studies showed that decreased CBR1 expression is associated with lymph node metastasis and poor prognosis in ovarian cancer, and induction of CBR1 expression in ovarian tumors leads to a spontaneous decrease in tumor size.[13]

Recent study demonstrates that CBR1 attenuates apoptosis and promotes cell survival in pancreatic β cell lines under glucotoxic and glucolipotoxic conditions via reducing ROS generation. Their data demonstrates that CBR1 expression level and enzyme activity are decreased in pancreatic islets isolated from db/db mice, an animal model of type 2 diabetes. These results suggest that CBR1 may play a role in protecting pancreatic β-cells against oxidative stress under glucotoxic or glucolipotoxic conditions, and its reduced expression or activity may contribute to β-cell dysfunction in db/db mice or human type 2 diabetes.[10]

In addition, CBR1 may play a critical role in prostaglandin F (PGF) synthesis in human amnion fibroblasts, and cortisol promotes the conversion of PGE2 into PGF via glucocorticoid receptor (GR)-mediated induction of CBR1 in human amnion fibroblasts. This stimulatory effect of cortisol on CBR1 expression may partly explain the concurrent increases of cortisol and PGF in human amnion tissue with labor, and these findings may account for the increased production of PGF in the fetal membranes prior to the onset of labor.[14]

Interactions

CBR1 has been shown to interact with Cortisol,[14] C2 domain,[15] and Flavonoid.[16]

References

  1. 1.0 1.1 1.2 1.3 "Entrez Gene: CBR1 carbonyl reductase 1". https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=873. 
  2. "Human carbonyl reductase (CBR) localized to band 21q22.1 by high-resolution fluorescence in situ hybridization displays gene dosage effects in trisomy 21 cells". Genomics 15 (1): 169–72. Jan 1993. doi:10.1006/geno.1993.1024. PMID 8432528. 
  3. "The SDR (short-chain dehydrogenase/reductase and related enzymes) nomenclature initiative". Chemico-Biological Interactions 178 (1–3): 94–8. Mar 2009. doi:10.1016/j.cbi.2008.10.040. PMID 19027726. 
  4. "Carbonyl reductase provides the enzymatic basis of quinone detoxication in man". Biochemical Pharmacology 35 (8): 1277–82. Apr 1986. doi:10.1016/0006-2952(86)90271-6. PMID 3083821. 
  5. "Carbonyl reductase: a novel metastasis-modulating function". Cancer Research 60 (5): 1173–6. Mar 2000. PMID 10728668. 
  6. "Neuroprotective role for carbonyl reductase?". Biochemical and Biophysical Research Communications 340 (4): 1019–22. Feb 2006. doi:10.1016/j.bbrc.2005.12.113. PMID 16406002. 
  7. "A functional genetic polymorphism on human carbonyl reductase 1 (CBR1 V88I) impacts on catalytic activity and NADPH binding affinity". Drug Metabolism and Disposition 35 (6): 973–80. Jun 2007. doi:10.1124/dmd.107.014779. PMID 17344335. 
  8. "Reference SNP Cluster Report: rs9024". Entrez SNP. National Center for Biotechnology Information/National Institutes of Health. https://www.ncbi.nlm.nih.gov/SNP/snp_ref.cgi?rs=9024. 
  9. "Pharmacogenetics of human carbonyl reductase 1 (CBR1) in livers from black and white donors". Drug Metabolism and Disposition 37 (2): 400–7. Feb 2009. doi:10.1124/dmd.108.024547. PMID 19022938. 
  10. 10.0 10.1 "Carbonyl reductase 1 protects pancreatic β-cells against oxidative stress-induced apoptosis in glucotoxicity and glucolipotoxicity". Free Radical Biology & Medicine 49 (10): 1522–33. Nov 2010. doi:10.1016/j.freeradbiomed.2010.08.015. PMID 20728534. 
  11. "Purification and properties of an NADPH-dependent carbonyl reductase from human brain. Relationship to prostaglandin 9-ketoreductase and xenobiotic ketone reductase". The Journal of Biological Chemistry 256 (3): 1206–13. Feb 1981. doi:10.1016/S0021-9258(19)69950-3. PMID 7005231. 
  12. 12.0 12.1 Murakami, A; Yakabe, K; Yoshidomi, K; Sueoka, K; Nawata, S; Yokoyama, Y; Tsuchida, S; Al-Mulla, F et al. (1 October 2012). "Decreased carbonyl reductase 1 expression promotes malignant behaviours by induction of epithelial mesenchymal transition and its clinical significance.". Cancer Letters 323 (1): 69–76. doi:10.1016/j.canlet.2012.03.035. PMID 22542806. 
  13. Osawa, Y; Yokoyama, Y; Shigeto, T; Futagami, M; Mizunuma, H (March 2015). "Decreased expression of carbonyl reductase 1 promotes ovarian cancer growth and proliferation.". International Journal of Oncology 46 (3): 1252–8. doi:10.3892/ijo.2014.2810. PMID 25572536. 
  14. 14.0 14.1 Guo, C; Wang, W; Liu, C; Myatt, L; Sun, K (August 2014). "Induction of PGF2α synthesis by cortisol through GR dependent induction of CBR1 in human amnion fibroblasts.". Endocrinology 155 (8): 3017–24. doi:10.1210/en.2013-1848. PMID 24654784. 
  15. Yagi, H; Conroy, PJ; Leung, EW; Law, RH; Trapani, JA; Voskoboinik, I; Whisstock, JC; Norton, RS (16 October 2015). "Structural Basis for Ca2+-mediated Interaction of the Perforin C2 Domain with Lipid Membranes.". The Journal of Biological Chemistry 290 (42): 25213–26. doi:10.1074/jbc.m115.668384. PMID 26306037. 
  16. Nelson, SH; Grunebaum, H (April 1971). "A follow-up study of wrist slashers.". The American Journal of Psychiatry 127 (10): 1345–9. doi:10.1176/ajp.127.10.1345. PMID 5549925. 

External links

Further reading