Pilpel Y, Sosinsky A, Lancet D
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
Essays Biochem. 1998;33:93-104. doi: 10.1042/bse0330093.
OR proteins bind odorant ligands and transmit a G-protein-mediated intracellular signal, resulting in generation of an action potential. The accumulation of DNA sequences of hundreds of OR genes provides an opportunity to predict features related to their structure, function and evolutionary diversification. The OR repertoire has evolved a variable ligand-binding site that ascertains recognition of multiple odorants, coupled to constant regions that mediate the cAMP-mediated signal transduction. The cellular second messenger underlies the responses to diverse odorants through the direct gating of olfactory-specific cation channels. This situation necessitates a mechanism of cellular exclusion, whereby each sensory neuron expresses only one receptor type, which in turn influences axonal projections. A 'synaptic image' of the OR repertoire thus encodes the detected odorant in the central nervous system.
嗅觉受体（OR）蛋白结合气味配体并传递G蛋白介导的细胞内信号，从而产生动作电位。数百个OR基因的DNA序列积累为预测与其结构、功能和进化多样化相关的特征提供了机会。OR基因库进化出了一个可变的配体结合位点，用于确定对多种气味的识别，并与介导cAMP介导的信号转导的恒定区域相连。细胞第二信使通过嗅觉特异性阳离子通道的直接门控作用，构成了对多种气味反应的基础。这种情况需要一种细胞排斥机制，即每个感觉神经元仅表达一种受体类型，这反过来又会影响轴突投射。因此，OR基因库的“突触图像”在中枢神经系统中编码检测到的气味。
