HETEROMERIC OLFACTORY CYCLIC NUCLEOTIDE-GATED CHANNELS - A SUBUNIT THAT CONFERS INCREASED SENSITIVITY TO CAMP
HETEROMERIC OLFACTORY CYCLIC NUCLEOTIDE-GATED CHANNELS - A SUBUNIT THAT CONFERS INCREASED SENSITIVITY TO CAMP
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DOI：
10.1073/pnas.91.19.8890
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发表时间：
1994-09-13
影响因子：
11.1
通讯作者：
ZINN, K
中科院分区：
文献类型：
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作者：
BRADLEY, J;LI, J;ZINN, K
嗅觉感受器神经元对气味刺激作出反应，细胞内cAMP迅速增加，打开环核苷酸门控(CNG)阳离子通道。CAMP在低微摩尔范围内激活大鼠嗅觉神经元的CNG通道，并呈外向整流性。然而，克隆的大鼠嗅觉CNG通道(ROCNC1)对cAMP的敏感性要低得多，并且表现出非常弱的整流性。在这里，我们描述了第二个大鼠CNG通道亚基的克隆和鉴定，标记为rOCNC2。当rOCNC2单独表达时，不能形成功能通道。然而，当rOCNC1和rOCNC2共表达时，观察到向外整流的阳离子电导，其cAMP敏感性接近天然通道。用针对这两个亚基的探针进行原位杂交表明，它们在嗅觉感受器神经元中共表达。这些数据表明，天然嗅觉CNG通道可能是rOCNC1和rOCNC2亚基的异源寡聚体。
Olfactory receptor neurons respond to odorant stimulation with a rapid increase in intracellular cAMP that opens cyclic nucleotide-gated (cng) cation channels. cng channels in rat olfactory neurons are activated by cAMP in the low micromolar range and are outwardly rectifying. The cloned rat olfactory cng channel (rOCNC1), however, is much less sensitive to cAMP and exhibits very weak rectification. Here we describe the cloning and characterization of a second rat cng channel subunit, denoted rOCNC2. rOCNC2 does not form functional channels when expressed alone. When rOCNC1 and rOCNC2 are coexpressed, however, an outwardly rectifying cation conductance with cAMP sensitivity near that of the native channel is observed. In situ hybridization with probes specific for the two subunits shows that they are coexpressed in olfactory receptor neurons. These data indicate that the native olfactory cng channel is likely to be a heterooligomer of the rOCNC1 and rOCNC2 subunits.