title: Activation of polycystic kidney disease-2-like 1 (PKD2L1)-PKD1L3 complex by acid in mouse taste cells.
abstract: Five basic tastes (bitter, sweet, umami, salty, and sour) are detected in the four taste areas where taste buds reside. Although molecular mechanisms for detecting bitter, sweet, and umami have been well clarified, those for sour and salty remain poorly understood. Several channels including acid-sensing ion channels have been proposed as candidate sour receptors, but they do not encompass all sour-sensing abilities in vivo. We recently reported a novel candidate for sour sensing, the polycystic kidney disease-2-like 1 (PKD2L1)-PKD1L3 channel complex. This channel is not a traditional ligand-gated channel and is gated open only after removal of an acid stimulus, called an off response. Here we show that off responses upon acid stimulus are clearly observed in native taste cells from circumvallate, but not fungiform papillae, of glutamate decarboxylase 67-green fluorescent protein (GAD67-GFP) knock-in mice, from which Type III taste cells can be visualized, using Ca(2+) imaging and patch clamp methods. Off responses were detected in most cells where PKD2L1 immunoreactivity was observed. Interestingly, the pH threshold for acid-evoked intracellular Ca(2+) increase was around 5.0, a value much higher than that observed in HEK293 cells expressing the PKD2L1-PKD1L3 complex. Thus, PKD2L1-PKD1L3-mediated acid-evoked off responses occurred both in HEK293 cells and in native taste cells, suggesting the involvement of the PKD2L1-PKD1L3 complex in acid sensing in vivo.
authors.affiliation: Division of Cell Signaling, Okazaki Institute for Integrative Bioscience, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8787, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yamanaka
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Uchida
authors.forename: Koji
authors.initials: K
authors.lastname: Shibasaki
authors.forename: Takaaki
authors.initials: T
authors.lastname: Sokabe
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Maruyama
authors.forename: Yuchio
authors.initials: Y
authors.lastname: Yanagawa
authors.forename: Shingo
authors.initials: S
authors.lastname: Murakami
authors.forename: Makoto
authors.initials: M
authors.lastname: Tominaga
mesh_terms: D000143:Acids / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011956:Receptors, Cell Surface / Q000378:metabolism*; D050396:TRPP Cation Channels / Q000378:metabolism*; D013649:Taste; D013650:Taste Buds / Q000378:metabolism*; D014059:Tongue / Q000378:metabolism
chemical_list: D000143:Acids; D015220:Calcium Channels; D007473:Ion Channels; C550142:PKD1L3 protein, human; C512453:PKD1L3 protein, mouse; C117185:PKD2L1 protein, human; C486487:Pkd2l1 protein, mouse; D011956:Receptors, Cell Surface; D050396:TRPP Cation Channels; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; D002118:Calcium
references.citation: Cell. 2001 Aug 10;106(3):381-90
references.pmid: 11509186
references.citation: Nature. 2001 Oct 11;413(6856):631-5
references.pmid: 11675786
references.citation: Nature. 1997 Mar 13;386(6621):173-7
references.pmid: 9062189
references.citation: J Neurosci. 2006 Apr 12;26(15):3971-80
references.pmid: 16611813
references.citation: Nature. 2010 Mar 11;464(7286):297-301
references.pmid: 20107438
references.citation: EMBO Rep. 2008 Jul;9(7):690-7
references.pmid: 18535624
references.citation: Annu Rev Neurosci. 1989;12:329-53
references.pmid: 2648951
references.citation: J Neurophysiol. 2004 Sep;92(3):1928-36
references.pmid: 15140906
references.citation: J Comp Neurol. 2000 Sep 11;425(1):139-51
references.pmid: 10940948
references.citation: J Comp Neurol. 2003 Dec 1;467(1):60-79
references.pmid: 14574680
references.citation: Chem Senses. 2008 Mar;33(3):243-54
references.pmid: 18156604
references.citation: Nature. 2006 Aug 24;442(7105):934-8
references.pmid: 16929298
references.citation: Proc Natl Acad Sci U S A. 2001 Jan 16;98(2):711-6
references.pmid: 11120882
references.citation: Cell. 2000 Mar 17;100(6):703-11
references.pmid: 10761935
references.citation: Physiol Behav. 1997 Nov;62(5):1137-43
references.pmid: 9333210
references.citation: Nat Neurosci. 2000 Feb;3(2):113-9
references.pmid: 10649565
references.citation: J Neurosci. 2003 Apr 1;23(7):2608-17
references.pmid: 12684446
references.citation: J Neurosci. 2006 Mar 1;26(9):2403-12
references.pmid: 16510717
references.citation: J Comp Neurol. 2000 Aug 21;424(2):205-15
references.pmid: 10906698
references.citation: Nature. 2002 Mar 14;416(6877):199-202
references.pmid: 11894099
references.citation: J Neurosci. 2004 Apr 21;24(16):4088-91
references.pmid: 15102924
references.citation: PLoS One. 2009 Oct 08;4(10):e7347
references.pmid: 19812697
references.citation: Nature. 1998 Oct 8;395(6702):555-6
references.pmid: 9783580
references.citation: Annu Rev Physiol. 1999;61:873-900
references.pmid: 10099714
references.citation: Proc Natl Acad Sci U S A. 2006 Aug 15;103(33):12569-74
references.pmid: 16891422
references.citation: J Physiol. 2009 Sep 15;587(Pt 18):4425-39
references.pmid: 19622604