title: The candidate sour taste receptor, PKD2L1, is expressed by type III taste cells in the mouse.
abstract: The transient receptor potential channel, PKD2L1, is reported to be a candidate receptor for sour taste based on molecular biological and functional studies. Here, we investigated the expression pattern of PKD2L1-immunoreactivity (IR) in taste buds of the mouse. PKD2L1-IR is present in a few elongate cells in each taste bud as reported previously. The PKD2L1-expressing cells are different from those expressing PLCbeta2, a marker of Type II cells. Likewise PKD2L1-immunoreactive taste cells do not express ecto-ATPase which marks Type I cells. The PKD2L1-positive cells are immunoreactive for neural cell adhesion molecule, serotonin, PGP-9.5 (ubiquitin carboxy-terminal transferase), and chromogranin A, all of which are present in Type III taste cells. At the ultrastructural level, PKD2L1-immunoreactive cells form synapses onto afferent nerve fibers, another feature of Type III taste cells. These results are consistent with the idea that different taste cells in each taste bud perform distinct functions. We suggest that Type III cells are necessary for transduction and/or transmission of information about "sour", but have little or no role in transmission of taste information of other taste qualities.
authors.affiliation: Department of Cell and Developmental Biology, University of Colorado at Denver and Health Science Center, Mail Stop 8108, P.O. Box 6511, Aurora, CO 80045, USA.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kataoka
authors.forename: Ruibiao
authors.initials: R
authors.lastname: Yang
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Ishimaru
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Matsunami
authors.forename: Jean
authors.initials: J
authors.lastname: Sévigny
authors.forename: John C
authors.initials: JC
authors.lastname: Kinnamon
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Finger
mesh_terms: D006916:5-Hydroxytryptophan / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002628:Chemoreceptor Cells / Q000166:cytology / Q000378:metabolism*; D053379:Chromogranin A / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007830:Larynx / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D008954:Models, Biological; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism; D010159:Palate / Q000378:metabolism; D010614:Pharynx / Q000378:metabolism; D054799:Phospholipase C beta / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism; D013650:Taste Buds / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D043222:Ubiquitin Thiolesterase / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D053379:Chromogranin A; D019006:Neural Cell Adhesion Molecules; C486487:Pkd2l1 protein, mouse; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D050053:TRPM Cation Channels; C498617:Trpm5 protein, mouse; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D006916:5-Hydroxytryptophan; D054799:Phospholipase C beta; C518037:Plcb2 protein, mouse; D043222:Ubiquitin Thiolesterase; C496976:Uchl1 protein, mouse; D000251:Adenosine Triphosphatases; C027201:ectoATPase