Transient receptor potential cation channel subfamily V member 5 is a calcium channelprotein that in humans is encoded by the TRPV5gene.[5][6][7]
Function
The TRPV5 gene is a member of the transient receptor family and the TRPV subfamily. The calcium-selective channel, TRPV5, encoded by this gene has 6 transmembrane-spanning domains, multiple potential phosphorylation sites, an N-linked glycosylation site, and 5 ANK repeats. This protein forms homotetramers or heterotetramers and is activated by a low internal calcium level.[8]
Both TRPV5 and TRPV6 are expressed in kidney and intestinalepithelial cells.[9] TRPV5 is mainly expressed in kidney epithelial cells, where it plays an important role in the reabsorption of Ca2+,[10] whereas TRPV6 is mainly expressed in the intestine.[9] The enzyme α-klotho increases kidney calcium reabsorption by stabilizing TPRV5.[9] Klotho is a beta-glucuronidase-like enzyme that activates TRPV5 by removal of sialic acid.[11]
Clinical significance
Normally, about 95% to 98% of Ca2+ filtered from the blood by the kidney is reabsorbed by the kidney's renal tubule, mediated by TRPV5.[12] Genetic deletion of TRPV5 in mice leads to Ca2+ loss in the urine, and consequential hyperparathyroidism, and bone loss.[13]
Autosomal recessive hypercalciuria has been described in a family with a missense, inactivating genetic variant in TRPV5. This variant, known as p.(Val598Met), affects the TRP helix region of TRPV5, which is thought to control channel pore gating, assembly and protein folding.[14]
Inhibitors
Econazole is a weak inhibitor of both TRPV5 and TRPV6, with an IC50 in the micromolar range
ZINC17988990 is a potent and selective inhibitor of TRPV5, with an IC50 of 177nM and good selectivity over TRPV6 and the other TRPV channel subtypes.[15]
↑"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
↑"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
↑Müller D, Hoenderop JG, Merkx GF, van Os CH, Bindels RJ (August 2000). "Gene structure and chromosomal mapping of human epithelial calcium channel". Biochemical and Biophysical Research Communications. 275 (1): 47–52. doi:10.1006/bbrc.2000.3227. PMID10944439.
↑Müller D, Hoenderop JG, Meij IC, van den Heuvel LP, Knoers NV, den Hollander AI, etal. (July 2000). "Molecular cloning, tissue distribution, and chromosomal mapping of the human epithelial Ca2+ channel (ECAC1)". Genomics. 67 (1): 48–53. doi:10.1006/geno.2000.6203. PMID10945469.
↑Clapham DE, Julius D, Montell C, Schultz G (December 2005). "International Union of Pharmacology. XLIX. Nomenclature and structure-function relationships of transient receptor potential channels". Pharmacological Reviews. 57 (4): 427–50. doi:10.1124/pr.57.4.6. PMID16382100. S2CID17936350.
123van Goor MK, Hoenderop JG, van der Wijst J (June 2017). "TRP channels in calcium homeostasis: from hormonal control to structure-function relationship of TRPV5 and TRPV6". Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1864 (6): 883–893. doi:10.1016/j.bbamcr.2016.11.027. PMID27913205.
Vennekens R, Droogmans G, Nilius B (September 2001). "Functional properties of the epithelial Ca2+ channel, ECaC". General Physiology and Biophysics. 20 (3): 239–53. PMID11765215.
Heiner I, Eisfeld J, Lückhoff A (2004). "Role and regulation of TRP channels in neutrophil granulocytes". Cell Calcium. 33 (5–6): 533–40. doi:10.1016/S0143-4160(03)00058-7. PMID12765698.
Nijenhuis T, Hoenderop JG, Bindels RJ (October 2005). "TRPV5 and TRPV6 in Ca(2+) (re)absorption: regulating Ca(2+) entry at the gate". Pflügers Archiv. 451 (1): 181–92. doi:10.1007/s00424-005-1430-6. PMID16044309. S2CID41267019.
Mensenkamp AR, Hoenderop JG, Bindels RJ (2007). "TRPV5, the gateway to Ca2+ homeostasis". Transient Receptor Potential (TRP) Channels. Handbook of Experimental Pharmacology. Vol.179. pp.207–20. doi:10.1007/978-3-540-34891-7_12. ISBN978-3-540-34889-4. PMID17217059.
Schoeber JP, Hoenderop JG, Bindels RJ (February 2007). "Concerted action of associated proteins in the regulation of TRPV5 and TRPV6". Biochemical Society Transactions. 35 (Pt 1): 115–9. doi:10.1042/BST0350115. PMID17233615.