The mammalian taste bud type III cell: A critical analysis

Murray, Raymond G.

doi:10.1016/0889-1605(86)90039-x

Cited by 85 publications

(69 citation statements)

References 24 publications

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“…2D, arrowheads). Type III cells appear to represent a relatively minor population of taste bud cells and are believed to display a single blunt apical microvillus that projects far up into the taste pore [41,44,45] (fig. 2D, arrow).…”

Section: Espins In the Microvillar Processes Of Other Sensory Cellsmentioning

confidence: 99%

Espins and the actin cytoskeleton of hair cell stereocilia and sensory cell microvilli

Sekerková

Zheng

Loomis

et al. 2006

Cell. Mol. Life Sci.

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The espins are novel actin-bundling proteins that are produced in multiple isoforms from a single gene. They are present at high concentration in the parallel actin bundle of hair cell stereocilia and are the target of deafness mutations in mice and humans. Espins are also enriched in the microvilli of taste receptor cells, solitary chemoreceptor cells, vomeronasal sensory neurons and Merkel cells, suggesting that espins play important roles in the microvillar projections of vertebrate sensory cells. Espins are potent actin-bundling proteins that are not inhibited by Ca 2+ . In cells, they efficiently elongate parallel actin bundles and, thereby, help determine the steady-state length of microvilli and stereocilia. Espins bind actin monomer via their WH2 domain and can assemble actin bundles in cells. Certain espin isoforms can also bind phosphatidylinositol 4,5-bisphosphate, profilins or SH3 proteins. These biological activities distinguish espins from other actin-bundling proteins and may make them well-suited to sensory cells. KeywordsEspin; actin; hair cell; stereocilia; microvilli; sensory; deafness; taste The stereocilia and microvilli of vertebrate sensory cells and their actinbundling proteinsMany classes of vertebrate sensory cells detect chemical or mechanical stimuli through microvilli or their derivatives, such as stereocilia. These relatively long-lived, fingerlike specializations of the plasma membrane are built around a common cytoskeletal element -the parallel actin bundle (PAB) [1]. PABs consist of tightly packed collections of actin filaments cross-linked by actin-bundling proteins. The filaments are aligned along their longitudinal axis and display a uniform polarity with respect to their preferred ends for actin monomer addition, which in microvilli and stereocilia is positioned at the distal tip. The PAB displays hallmarks of a supramolecular scaffold that determines the placement, dimensions, flexibility and signaling properties of microvilli and stereocilia. Although filopodia also contain a PAB at their core and are believed to sense the local environment, they are considerably more dynamic and differ significantly from microvilli and stereocilia in their molecular composition and biogenesis [2].

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Section: Espins In the Microvillar Processes Of Other Sensory Cellsmentioning

confidence: 99%

Espins and the actin cytoskeleton of hair cell stereocilia and sensory cell microvilli

Sekerková

Zheng

Loomis

et al. 2006

Cell. Mol. Life Sci.

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“…α-gustducin-knockout mice are insensitive to bitter tastants [11], linking this particular marker to the bitter sensitive subpopulation of type II cells [12]. Type III cells transduce sour stimuli [13,14] and salty [15], and form synapses with nerve fibers [16-20]. This latter cell type expresses NCAM [21] and is serotonin immunopositive [22], as well as immunoreactive for SNAP-25 [23].…”

Section: Introductionmentioning

confidence: 99%

Differential expression of a BMP4 reporter allele in anterior fungiform versus posterior circumvallate taste buds of mice

Nguyen

Barlow

2010

BMC Neurosci

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BackgroundBone Morphogenetic Protein 4 (BMP4) is a diffusible factor which regulates embryonic taste organ development. However, the role of BMP4 in taste buds of adult mice is unknown. We utilized transgenic mice with LacZ under the control of the BMP4 promoter to reveal the expression of BMP4 in the tongues of adult mice. Further we evaluate the pattern of BMP4 expression with that of markers of specific taste bud cell types and cell proliferation to define and compare the cell populations expressing BMP4 in anterior (fungiform papillae) and posterior (circumvallate papilla) tongue.ResultsBMP4 is expressed in adult fungiform and circumvallate papillae, i.e., lingual structures composed of non-taste epithelium and taste buds. Unexpectedly, we find both differences and similarities with respect to expression of BMP4-driven ß-galactosidase. In circumvallate papillae, many fusiform cells within taste buds are BMP4-ß-gal positive. Further, a low percentage of BMP4-expressing cells within circumvallate taste buds is immunopositive for markers of each of the three differentiated taste cell types (I, II and III). BMP4-positive intragemmal cells also expressed a putative marker of immature taste cells, Sox2, and consistent with this finding, intragemmal cells expressed BMP4-ß-gal within 24 hours after their final mitosis, as determined by BrdU birthdating. By contrast, in fungiform papillae, BMP4-ß-gal positive cells are never encountered within taste buds. However, in both circumvallate and fungiform papillae, BMP4-ß-gal expressing cells are located in the perigemmal region, comprising basal and edge epithelial cells adjacent to taste buds proper. This region houses the proliferative cell population that gives rise to adult taste cells. However, perigemmal BMP4-ß-gal cells appear mitotically silent in both fungiform and circumvallate taste papillae, as we do not find evidence of their active proliferation using cell cycle immunomarkers and BrdU birthdating.ConclusionOur data suggest that intragemmal BMP4-ß-gal cells in circumvallate papillae are immature taste cells which eventually differentiate into each of the 3 taste cell types, whereas perigemmal BMP4-ß-gal cells in both circumvallate and fungiform papillae may be slow cycling stem cells, or belong to the stem cell niche to regulate taste cell renewal from the proliferative cell population.

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“…Type II cells are specialized taste receptor cells that are believed to recognize bitter, sweet and umami stimuli (Clapp et al, 2001(Clapp et al, , 2004Miyoshi et al, 2001;Nelson et al, 2001;Zhang et al, 2003). Type III cells, which are also considered to be taste receptor cells, were first identified in the foliate papillae in the rabbit (Murray, 1986) and later in the rhesus monkey (Farbman et al, 1985), mouse (Takeda, 1976;Takeda et al, 1989) and rat (Yee et al, 2001). Type III cells represent ~5-15% of the taste bud cell population, display a single blunt apical microvillus, exhibit serotonin immunoreactivity and show synaptic innervation (Murray et al, 1969;Royer & Kinnamon, 1988;Yee et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, however, taste buds have been shown to house a much more diverse population of cell types. The sensory cells are now further categorized on the basis of microscopic features and cell type-specific markers into type II and type III cells (Murray, 1986;Yee et al, 2001), while the supporting cells remain designated as type I cells. Type II cells are specialized taste receptor cells that are believed to recognize bitter, sweet and umami stimuli (Clapp et al, 2001(Clapp et al, , 2004Miyoshi et al, 2001;Nelson et al, 2001;Zhang et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Espin cytoskeletal proteins in the sensory cells of rodent taste buds

et al. 2005

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Espins are multifunctional actin-bundling proteins that are highly enriched in the microvilli of certain chemosensory and mechanosensory cells, where they are believed to regulate the integrity and/or dimensions of the parallel-actin-bundle cytoskeletal scaffold. We have determined that, in rats and mice, affinity purified espin antibody intensely labels the lingual and palatal taste buds of the oral cavity and taste buds in the pharyngo-laryngeal region. Intense immunolabeling was observed in the apical, microvillar region of taste buds, while the level of cytoplasmic labeling in taste bud cells was considerably lower. Taste bud cells contain tightly packed collections of sensory cells (light, or type II plus type III) and supporting cells (dark, or type I), which can be distinguished by microscopic features and cell type-specific markers. On the basis of results obtained using an antigen-retrieval method in conjunction with double immunofluorescence for espin and sensory taste cell-specific markers, we propose that espins are expressed predominantly in the sensory cells of rat circumvallate taste buds. In confocal images, we counted 21.5±0.3 espin-positive cells/taste bud, in agreement with a previous report showing 20.7±1.3 light cells/ taste bud when counted at the ultrastructural level. The espin antibody labeled spindle-shaped cells with round nuclei and showed 100% colocalization with cell-specific markers recognizing all type II [inositol 1,4,5-trisphosphate receptor type III (IP 3 R 3 ),α-gustducin, protein-specific gene product 9.5 (PGP9.5)] and a subpopulation of type III (IP 3 R 3 , PGP9.5) taste cells. On average, 72%, 50%, and 32% of the espin-positive taste cells were labeled with antibodies to IP 3 R 3 , α-gustducin, and PGP9.5, respectively. Upon sectional analysis, the taste buds of rat circumvallate papillae commonly revealed a multi-tiered, espin-positive apical cytoskeletal apparatus. One espin-positive zone, a collection of ~3 μm-long microvilli occupying the taste pore, was separated by an espindepleted zone from a second espin-positive zone situated lower within the taste pit. This latter zone included espin-positive rod-like structures that occasionally extended basally to a depth of 10-12 μm into the cytoplasm of taste cells. We propose that the espin-positive zone in the taste pit coincides with actin bundles in association with the microvilli of type II taste cells, whereas the espin-positive microvilli in the taste pore are the single microvilli of type III taste cells.

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The mammalian taste bud type III cell: A critical analysis

Cited by 85 publications

References 24 publications

Espins and the actin cytoskeleton of hair cell stereocilia and sensory cell microvilli

Espins and the actin cytoskeleton of hair cell stereocilia and sensory cell microvilli

Differential expression of a BMP4 reporter allele in anterior fungiform versus posterior circumvallate taste buds of mice

Espin cytoskeletal proteins in the sensory cells of rodent taste buds

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