Synaptic vesicle glycoprotein 2B (SV2B), a regulator of synaptic vesicle exocytosis, is expressed in PKD2L1 cells, suggesting that this taste cell population transmits tastant information to gustatory afferent nerve fibers via exocytic neurotransmitter release.
TMEM44 cells may comprise a developing taste cell population since immature, basal cells in the bottom of the taste bud express SHH, a growth factor involved in taste bud development [12], [27], [28], and TMEM44 signals partially overlapped with SHH signals.
Alternatively, since this taste cell population releases neurotransmitters by exocytosis onto afferent nerve fibers, and since the yeast homolog of IKBKAP, Elp1p, interacts with the post-Golgi vesicular transport component Sec2p [51], IKBKAP may regulate polarized exocytosis of signaling components in sour taste cells.
Using double label ISH, MTCP1 and TRPM5 labeled similar taste cell populations (Fig. 4C H, O) while MCTP1 and PKD1L3 labeled distinct taste cell populations (Fig. 4I N, P).
Using double label ISH, TRPM5 and PKD1L3 labeled distinct taste cell populations (Fig. 1A F,M), whereas PKD2L1 and PKD1L3 largely labeled the same taste cell population (Fig. 1G L,N).
TMEM44 and PKD1L3 also labeled distinct taste cell populations in CV (Fig. 2F H) and FG (Fig. 2L N) taste buds.
Expression of genes in specific taste cell populations provides novel insights into the processes and pathways active in gustation.
Using double label ISH, TMEM44 and TRPM5 labeled distinct taste cell populations in CV (Fig. 2C E) and FG (Fig. 2I K) taste buds.
Localization of transcripts to TRPM5, PKD1L3, and SHH taste cell populations suggests the possible functions of these gene products in taste.
SV2B and TRPM5 labeled distinct taste cell populations (Fig. 9C E, I) while SV2B and PKD1L3 expression patterns overlapped (Fig. 9F H, J), in double label ISH analyses.
