Lemay G, Zollinger M, Waksman G, Roques B P, Crine P, Boileau G
Département de Biochimie, Faculté de Médecine, Université de Montréal, Québec, Canada.
Biochem J. 1990 Apr 15;267(2):447-52. doi: 10.1042/bj2670447.
Neutral endopeptidase-24.11 (EC 3.4.24.11) (NEP) is a transmembrane metallo-endopeptidase that has been shown to be involved in the degradation of several mammalian neuropeptides, including enkephalins. The enzyme has recently been found to be specifically associated with the axonal and synaptic membranes of neurons in the globus pallidus of the pig brain. This result suggests that neurons must possess mechanisms for targeting NEP to particular membrane domains. Study of these mechanisms would greatly benefit from the existence of an established neuron-like cell line capable of expressing and targeting NEP to specific membrane domains. For this reason we have used a retroviral vector containing the cDNA for rabbit kidney NEP to express this enzyme in a mouse neuroblastoma cell line (Neuro2A). Labelling of the cell surface with an antibody coupled to colloidal gold particles and examination of the cells by electron microscopy revealed a non-uniform distribution of NEP at the surface of the cells, the protein being preferentially associated with the membrane of neurites compared with the cell body. This observation suggests that Neuro2A cells possess a mechanism for targeting NEP to specific domains of the plasma membrane. This cell line could thus constitute a good model for studying the mechanisms responsible for targeting this enzyme to specialized regions of the plasma membrane.
中性内肽酶-24.11（EC 3.4.24.11）（NEP）是一种跨膜金属内肽酶，已被证明参与多种哺乳动物神经肽的降解，包括脑啡肽。最近发现该酶与猪脑苍白球中神经元的轴突膜和突触膜特异性相关。这一结果表明，神经元必须具备将NEP靶向特定膜结构域的机制。如果存在一种能够表达NEP并将其靶向特定膜结构域的成熟的神经元样细胞系，那么对这些机制的研究将大有裨益。因此，我们使用了一种含有兔肾NEP cDNA的逆转录病毒载体，在小鼠神经母细胞瘤细胞系（Neuro2A）中表达这种酶。用与胶体金颗粒偶联的抗体对细胞表面进行标记，并通过电子显微镜检查细胞，结果显示NEP在细胞表面分布不均匀，与细胞体相比，该蛋白优先与神经突膜相关。这一观察结果表明，Neuro2A细胞具备将NEP靶向质膜特定结构域的机制。因此，该细胞系可构成一个很好的模型，用于研究将这种酶靶向质膜特定区域的机制。
