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TRPN

From Wikipedia, the free encyclopedia

TRPNis a member of thetransient receptor potential channelfamilyofion channels,which is a diverse group of proteins thought to be involved in mechanoreception.[1]The TRPN gene was given the nameno mechanoreceptor potential C(nompC) when it was first discovered infruit flies,[2]hence theNin TRPN. Since its discovery in fruit flies, TRPNhomologshave been discovered and characterized inworms,[3]frogs,[4]andzebrafish.[5]

Structure

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A structure of NOMPC was published in 2017, solved using electron cryo-microscopy.[6]X-ray crystallographystudies of channel segments cloned from fruit flies and zebrafish have led to the hypothesis that multipleankyrin repeatsat TRPN'sN-terminusare involved in the gating of the channel pore.[7]Crystallography studies of TRPY1, ayeastTRP homolog,[8]have shown thataromatic residuesconserved across TRP family members, including TRPN, in the sixthtransmembrane domainare critical to the gating mechanism as well.[7]

Function

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As amechanoreceptor,TRPN responds to impinging mechanical forces. Studies in TRPN deficient adult fruit flies and larvae have shown that thesenullmutantshave severe difficultymoving,which suggests a role for TRPN inproprioception.[9]This hypothesis is further strengthened byimmunostainingstudies in fruit flies that have shown TRPNlocalizationin the cilia ofcampaniform sensillaandchordotonal organsinJohnston's organ.[10]Further immunostaining studies in fruit flies have identified, with higherresolutiontechniques, that TRPN is localized at the distal end of motile mechanosensory cilia in Johnston's organ.[11]However, TRPN is not required for transduction of mechanical stimuli in larvae[12]or adult flies,[13]suggesting that theTRPVchannelsnanchungandinactivemay also serve a mechanosensory function.[13]

Studies in worms have shown that TRPN mutants have locomotion defects, as well as a decreased basal slowing response, which is a reduction in rate of motion that is induced by contact with a food source.[3]This result further strengthens the hypothesis that TRPN is vital to proprioception.Electrophysiologicalstudies of single channels in worms have shown that TRPN responds to mechanical stimuli and has a preference forsodiumions,[14]although a complete ion selectivity profile has yet to be identified.

Studies in zebrafish larvae have also shown thatmorpholino-mediatedknockdownof TRPN function result in deafness as well as imbalance,[5]suggesting a dual role in hearing as well as proprioception. Immunostaining studies in frog embryos have shown localization of TRPN at the tips of mechanosensory cilia in thelateral line,hair cellsand ciliatedepidermalcells,[4]suggesting a role in a variety of mechanosensory functions. TRPN localizes to the kinocilia, not stereocilia, of amphibian hair cells, suggesting the presence of two distinct classes of mechanosensitive channel.

TRPN has the capability of performing a variety of roles in mechanosensory systems.[citation needed]

Genes

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Genomic data from a variety of organisms show that TRPN is present in mostanimals,but it is absent in allamniotes.[15]In most animals the number ofankyrin repeatsis between 28 and 29.

The following is a list of genes encoding TRPN organized by the organism in which they are found. Gene names are specific to the organism and to the way in which they were discovered, which is why the gene name may not explicitly be "TRPN". Links to theNCBIGene database are included whenever possible.

Fruit fly (Drosophila melanogaster)

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Nematode worm (Caenorhabditis elegans)

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African clawed frog (Xenopus laevis)

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Zebrafish (Danio rerio)

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References

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  1. ^Duggan, A.; García-Añoveros, J.; Corey, D. P. (2000)."Insect mechanoreception: What a long, strange TRP it's been".Current Biology.10(10): R384–R387.Bibcode:2000CBio...10.R384D.doi:10.1016/s0960-9822(00)00478-4.PMID10837217.
  2. ^Walker, R. G.; Willingham, A. T.; Zuker, C. S. (2000). "A Drosophila mechanosensory transduction channel".Science.287(5461): 2229–2234.Bibcode:2000Sci...287.2229W.CiteSeerX10.1.1.646.2497.doi:10.1126/science.287.5461.2229.PMID10744543.
  3. ^abLi, W.; Feng, Z.; Sternberg, P. W.; Shawn Xu, X. Z. (2006)."A C. Elegans stretch receptor neuron revealed by a mechanosensitive TRP channel homologue".Nature.440(7084): 684–687.Bibcode:2006Natur.440..684L.doi:10.1038/nature04538.PMC2865900.PMID16572173.
  4. ^abShin, J. -B.; Adams, D.; Paukert, M.; Siba, M.; Sidi, S.; Levin, M.; Gillespie, P. G.; Gründer, S. (2005)."Xenopus TRPN1 (NOMPC) localizes to microtubule-based cilia in epithelial cells, including inner-ear hair cells".Proceedings of the National Academy of Sciences.102(35): 12572–12577.Bibcode:2005PNAS..10212572S.doi:10.1073/pnas.0502403102.PMC1194908.PMID16116094.
  5. ^abSidi, S.; Friedrich, R. W.; Nicolson, T. (2003)."NompC TRP Channel Required for Vertebrate Sensory Hair Cell Mechanotransduction".Science.301(5629): 96–99.Bibcode:2003Sci...301...96S.doi:10.1126/science.1084370.PMID12805553.S2CID23882972.
  6. ^Jin, Peng; Bulkley, David; Guo, Yanmeng; Zhang, Wei; Guo, Zhenhao; Huynh, Walter; Wu, Shenping; Meltzer, Shan; Cheng, Tong (July 2017)."Electron cryo-microscopy structure of the mechanotransduction channel NOMPC".Nature.547(7661): 118–122.Bibcode:2017Natur.547..118J.doi:10.1038/nature22981.ISSN1476-4687.PMC5669069.PMID28658211.
  7. ^abHoward, J.; Bechstedt, S. (2004)."Hypothesis: A helix of ankyrin repeats of the NOMPC-TRP ion channel is the gating spring of mechanoreceptors".Current Biology.14(6): R224–R226.Bibcode:2004CBio...14.R224H.doi:10.1016/j.cub.2004.02.050.PMID15043829.
  8. ^Palmer, C. P.; Zhou, X. L.; Lin, J.; Loukin, S. H.; Kung, C.; Saimi, Y. (2001)."A TRP homolog in Saccharomyces cerevisiae forms an intracellular Ca2+-permeable channel in the yeast vacuolar membrane".Proceedings of the National Academy of Sciences.98(14): 7801–7805.doi:10.1073/pnas.141036198.PMC35422.PMID11427713.
  9. ^Cheng, L. E.; Song, W.; Looger, L. L.; Jan, L. Y.; Jan, Y. N. (2010)."The role of the TRP channel NompC in Drosophila larval and adult locomotion".Neuron.67(3): 373–380.doi:10.1016/j.neuron.2010.07.004.PMC2933178.PMID20696376.
  10. ^Liang, X.; Madrid, J.; Saleh, H. S.; Howard, J. (2011)."NOMPC, a Member of the TRP Channel Family, Localizes to the Tubular Body and Distal Cilium of Drosophila Campaniform and Chordotonal Receptor Cells".Cytoskeleton.68(1): 1–7.doi:10.1002/cm.20493.PMC3048163.PMID21069788.
  11. ^Lee, J.; Moon, S.; Cha, Y.; Chung, Y. D. (2010). Gonzalez, Cayetano (ed.)."Drosophila TRPN( =NOMPC) Channel Localizes to the Distal End of Mechanosensory Cilia".PLOS ONE.5(6): e11012.Bibcode:2010PLoSO...511012L.doi:10.1371/journal.pone.0011012.PMC2882365.PMID20543979.
  12. ^Zhang, W; Yan, Z; Jan, L. Y.; Jan, Y. N. (2013)."Sound response mediated by the TRP channels NOMPC, NANCHUNG, and INACTIVE in chordotonal organs of Drosophila larvae".Proceedings of the National Academy of Sciences.110(33): 13612–7.Bibcode:2013PNAS..11013612Z.doi:10.1073/pnas.1312477110.PMC3746866.PMID23898199.
  13. ^abLehnert, B. P.; Baker, A. E.; Gaudry, Q; Chiang, A. S.; Wilson, R. I. (2013)."Distinct roles of TRP channels in auditory transduction and amplification in Drosophila".Neuron.77(1): 115–28.doi:10.1016/j.neuron.2012.11.030.PMC3811118.PMID23312520.
  14. ^Kang, L.; Gao, J.; Schafer, W. R.; Xie, Z.; Xu, X. Z. S. (2010)."C. Elegans TRP family protein TRP-4 is a pore-forming subunit of a native mechanotransduction channel".Neuron.67(3): 381–391.doi:10.1016/j.neuron.2010.06.032.PMC2928144.PMID20696377.
  15. ^Schüler, Andreas; Schmitz, Gregor; Reft, Abigail; Özbek, Suat; Thurm, Ulrich; Bornberg-Bauer, Erich (June 2015)."The Rise and Fall of TRP-N, an Ancient Family of Mechanogated Ion Channels, in Metazoa".Genome Biology and Evolution.7(6): 1713–1727.doi:10.1093/gbe/evv091.PMC4494053.PMID26100409.
  16. ^NCBI Genbank entry
  17. ^NCBI Genbank entry
  18. ^NCBI Genbank entry
  19. ^NCBI Genbank entry
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