CHRNA9 explained

Neuronal acetylcholine receptor subunit alpha-9, also known as nAChRα9, is a protein that in humans is encoded by the CHRNA9 gene.^[1] The protein encoded by this gene is a subunit of certain nicotinic acetylcholine receptors (nAchR).

α9 subunit-containing receptors are notably blocked by nicotine. The role of this antagonism in the effects of tobacco are unknown.

This gene is a member of the ligand-gated ionic channel family and nicotinic acetylcholine receptor gene superfamily. It encodes a plasma membrane protein that forms homo- or hetero-oligomeric divalent cation channels. This protein is involved in cochlea hair cell function and is expressed in both the inner and outer hair cells (OHCs) of the adult cochlea, although expression levels in adult inner hair cells is low. The activation of the alpha9/10 nAChR is via olivocochlear activity, represented by cholinergic efferent synaptic terminals originating from the superior olive region of the brainstem. The protein is additionally expressed in keratinocytes, the pituitary gland, B-cells and T-cells.

Selective block of α9α10 nicotinic acetylcholine receptors by the conotoxin RgIA has been shown to be analgesic in an animal model of nerve injury pain.^[2]

See also

• Nicotinic acetylcholine receptor

Further reading

• Nguyen VT, Ndoye A, Grando SA . Novel Human α9 Acetylcholine Receptor Regulating Keratinocyte Adhesion is Targeted by Pemphigus Vulgaris Autoimmunity . Am. J. Pathol. . 157 . 4 . 1377–1391 . 2000 . 11021840 . 10.1016/S0002-9440(10)64651-2. 1850172 .
• Hartley JL, Temple GF, Brasch MA . DNA Cloning Using In Vitro Site-Specific Recombination . Genome Res. . 10 . 11 . 1788–1795 . 2001 . 11076863 . 10.1101/gr.143000 . 310948 .
• Sgard F, Charpantier E, Bertrand S . A novel human nicotinic receptor subunit, alpha10, that confers functionality to the alpha9-subunit . Mol. Pharmacol. . 61 . 1 . 150–159 . 2002 . 11752216 . 10.1124/mol.61.1.150 . 42831541 . etal.
• Strausberg RL, Feingold EA, Grouse LH . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–16903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . etal. free .
• Lustig LR, Peng H . Chromosome location and characterization of the human nicotinic acetylcholine receptor subunit alpha (alpha) 9 (CHRNA9) gene . Cytogenet. Genome Res. . 98 . 2–3 . 154–159 . 2003 . 12697997 . 10.1159/000069804 . 30207588 .
• Valor LM, Castillo M, Ortiz JA, Criado M . Transcriptional regulation by activation and repression elements located at the 5'-noncoding region of the human alpha9 nicotinic receptor subunit gene . J. Biol. Chem. . 278 . 39 . 37249–37255 . 2003 . 12860975 . 10.1074/jbc.M307043200 . free . 10261/338645 . free .
• Gerhard DS, Wagner L, Feingold EA . The Status, Quality, and Expansion of the NIH Full-Length cDNA Project: The Mammalian Gene Collection (MGC) . Genome Res. . 14 . 10B . 2121–2127 . 2004 . 15489334 . 10.1101/gr.2596504 . 528928 . etal.
• Peng H, Ferris RL, Matthews T . Characterization of the human nicotinic acetylcholine receptor subunit alpha (alpha) 9 (CHRNA9) and alpha (alpha) 10 (CHRNA10) in lymphocytes . Life Sci. . 76 . 3 . 263–280 . 2004 . 15531379 . 10.1016/j.lfs.2004.05.031 . etal.
• Hillier LW, Graves TA, Fulton RS . Generation and annotation of the DNA sequences of human chromosomes 2 and 4 . Nature . 434 . 7034 . 724–731 . 2005 . 15815621 . 10.1038/nature03466 . 2005Natur.434..724H . etal. free .
• Chernyavsky AI, Arredondo J, Vetter DE, Grando SA . CENTRAL ROLE OF α9 ACETYLCHOLINE RECEPTOR IN COORDINATING KERATINOCYTE ADHESION AND MOTILITY AT THE INITIATION OF EPITHELIALIZATION . Exp. Cell Res. . 313 . 16 . 3542–3555 . 2007 . 17706194 . 10.1016/j.yexcr.2007.07.011 . 2682983 .

Notes and References

1. Web site: Entrez Gene: CHRNA9 cholinergic receptor, nicotinic, alpha 9.
2. Vincler M, Wittenauer S, Parker R, Ellison M, Olivera BM, McIntosh JM . Molecular mechanism for analgesia involving specific antagonism of α9α10 nicotinic acetylcholine receptors . Proc. Natl. Acad. Sci. U.S.A. . 103 . 47 . 17880–17884 . November 2006 . 17101979 . 1635975 . 10.1073/pnas.0608715103 . 2006PNAS..10317880V . free .