Stephan Aaron B, Shum Eleen Y, Hirsh Sarah, Cygnar Katherine D, Reisert Johannes, Zhao Haiqing
Department of Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21218, USA.
Proc Natl Acad Sci U S A. 2009 Jul 14;106(28):11776-81. doi: 10.1073/pnas.0903304106. Epub 2009 Jun 26.
For vertebrate olfactory signal transduction, a calcium-activated chloride conductance serves as a major amplification step. However, the molecular identity of the olfactory calcium-activated chloride channel (CaCC) is unknown. Here we report a proteomic screen for cilial membrane proteins of mouse olfactory sensory neurons (OSNs) that identified all the known olfactory transduction components as well as Anoctamin 2 (ANO2). Ano2 transcripts were expressed specifically in OSNs in the olfactory epithelium, and ANO2::EGFP fusion protein localized to the OSN cilia when expressed in vivo using an adenoviral vector. Patch-clamp analysis revealed that ANO2, when expressed in HEK-293 cells, forms a CaCC and exhibits channel properties closely resembling the native olfactory CaCC. Considering these findings together, we propose that ANO2 constitutes the olfactory calcium-activated chloride channel.
对于脊椎动物的嗅觉信号转导而言,钙激活氯离子电导是一个主要的放大步骤。然而,嗅觉钙激活氯离子通道(CaCC)的分子身份尚不清楚。在此,我们报告了一项针对小鼠嗅觉感觉神经元(OSN)纤毛膜蛋白的蛋白质组学筛选,该筛选鉴定出了所有已知的嗅觉转导成分以及anoctamin 2(ANO2)。Ano2转录本在嗅觉上皮中的OSN中特异性表达,并且当使用腺病毒载体在体内表达时,ANO2::EGFP融合蛋白定位于OSN纤毛。膜片钳分析显示,ANO2在HEK-293细胞中表达时形成一个CaCC,并表现出与天然嗅觉CaCC非常相似的通道特性。综合这些发现,我们提出ANO2构成嗅觉钙激活氯离子通道。