Inward rectifier channel, ROMK, is localized to the apical tips of glial-like cells in mouse taste buds.
Inward rectifier channel, ROMK, is localized to the apical tips of glial-like cells in mouse taste buds.
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DOI：
10.1002/cne.22152
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发表时间：
2009-11-01
期刊：
影响因子：
--
通讯作者：
Chaudhari N
中科院分区：
文献类型：
--
作者：
Dvoryanchikov G;Sinclair MS;Perea-Martinez I;Wang T;Chaudhari N
味蕾中的细胞紧密排列，几乎没有细胞外空间。紧密连接和其他屏障进一步限制渗透性，并可能导致细胞外K+在动作电位后积聚。在许多组织中，内向整流钾通道，如肾外髓质钾（ROMK）通道（也称为Kir1.1，来源于Kcnj 1基因）有助于重新分配K+。使用RT-PCR，我们定义了小鼠肾脏中的ROMK剪接变体，并在此报告了其中一个ROMK 2在小鼠味觉细胞亚群中的表达。qRT-PCR结果显示，ROMK mRNA在味蕾中的表达丰度为齿状突>叶状突>菌状突。ROMK蛋白遵循与mRNA相同的流行模式，并且在真菌状味蕾中基本上无法通过免疫组织化学检测到。ROMK蛋白定位于味觉细胞亚群的顶端。使用PLCβ2-GFP和GAD-GFP转基因小鼠的组织，我们发现在表达PLCβ2的II型/受体细胞或表达GAD的III型/突触前细胞中未发现ROMK。相反，ROMK被发现，通过单细胞RT-PCR和免疫荧光，在大多数细胞是阳性的味觉神经胶质细胞标志物，外核苷酸酶2。ROMK精确地定位于这些细胞的顶端，在顶端紧密连接处和上方。我们建议，在味蕾中，ROMK在I型/神经胶质样细胞可以提供一个自我平衡的功能，通过顶孔分泌多余的K+，并允许兴奋的味觉细胞，以保持超极化的静息膜电位。
Cells in taste buds are closely packed with little extracellular space. Tight junctions and other barriers further limit permeability and may result in buildup of extracellular K+ following action potentials. In many tissues, inwardly-rectifying K channels such as the Renal Outer Medullary K (ROMK) channel (also called Kir1.1 and derived from the Kcnj1 gene) help to redistribute K+. Using RT-PCR, we defined ROMK splice variants in mouse kidney, and report here the expression of a single one of these, ROMK2, in a subset of mouse taste cells. With qRT-PCR, we show the abundance of ROMK mRNA in taste buds is vallate > foliate ≫ palate ≫ fungiform. ROMK protein follows the same pattern of prevalence as mRNA, and is essentially undetectable by immunohistochemistry in fungiform taste buds. ROMK protein is localized to the apical tips of a subset of taste cells. Using tissues from PLCβ2-GFP and GAD-GFP transgenic mice, we show that ROMK is not found in PLCβ2-expressing type II/Receptor cells or in GAD-expressing type III/Presynaptic cells. Instead, ROMK is found, by single-cell RT-PCR and immunofluorescence, in most cells that are positive for the taste glial cell marker, Ectonucleotidase2. ROMK is precisely localized to the apical tips of these cells, at and above apical tight junctions. We propose that in taste buds, ROMK in type I/glial-like cells may serve a homeostatic function, excreting excess K+ through the apical pore, and allowing excitable taste cells to maintain a hyperpolarized resting membrane potential.
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影响因子：
6.2
作者：
Kofuji, P;Biedermann, B;Reichenbach, A
通讯作者：
Reichenbach, A
DOI：
10.1152/ajprenal.1997.273.4.f516
发表时间：
1997-10-01
影响因子：
4.2
作者：
Choe, H;Zhou, H;Sackin, H
通讯作者：
Sackin, H
DOI：
10.1152/ajpcell.1999.276.3.c585
发表时间：
1999-03-01
影响因子：
5.5
作者：
Beesley, AH;Ortega, B;White, SJ
通讯作者：
White, SJ
影响因子：
5.4
作者：
Clapp, TR;Medler, KF;Kinnamon, SC
通讯作者：
Kinnamon, SC
影响因子：
5.3
作者：
DeFazio, RA;Dvoryanchikov, G;Chaudhari, N
通讯作者：
Chaudhari, N