EXTRACELLULAR MATRIX NERVE TERMINAL ANCHORAGE PROTEINS

没有突触前膜蛋白的锚神经末梢到 细胞外基质（ECM）是已知的。 我的研究目标是 来鉴定和描述一些与锚定有关的蛋白质 神经末梢 这些蛋白质可以介导众所周知的营养性 神经终末与基底膜的相互作用 再生 因此，特别感兴趣的是那些蛋白质， 是特定于一组突触的 我们已经从板鳃类电器中鉴定出一种蛋白多糖， 具有这种锚定蛋白的一些特征。 发现 在神经末梢表面限制于突触区域。 是 与细胞外基质（ECM）部分紧密结合并富集于其中。 有趣的是，这种蛋白聚糖含有抗原决定簇， 只与电器官神经元有关。 最后，Synaptic 囊泡还含有一种跨膜蛋白聚糖， 抗原决定簇 因此，突触囊泡也可能含有这种物质。 相同的蛋白聚糖。 根据这些数据，我们假设这种蛋白多糖是突触前的 连接神经末梢和ECM的膜蛋白。 此外，本发明还提供了一种方法， 突触囊泡可以作为载体， 和神经末梢表面。 本研究有两个基本目标：1）确定有效性 2）识别和表征其他突触前神经元， 锚突触ECM的膜蛋白。 要实现第一个目标，需要采取几个步骤。 我们将确定 蛋白聚糖是否是一种完整的膜蛋白， 缺乏疏水性尾部。 我们将确定ECM组件， 结合蛋白聚糖。 如果蛋白聚糖是一种膜蛋白 并结合ECM成分，它必须将神经末梢连接到基质。 如果这种连接是通过途径特异性抗原决定簇， 连接可能是这个突触特有的。 一个生化的比较， 突触囊泡和ECM蛋白聚糖蛋白核心将决定 这两种分子可以共享一种底物-产物关系。 到 为了实现第二个目标，我们将使用ECM部分，其中神经 末端蛋白聚糖最初被发现。我们将分离一个亚组分 含有ECM材料中所含的整合膜蛋白。 如果突触前膜蛋白（除了蛋白聚糖）结合到 ECM，它们应该存在于该亚组分中。 通过制造单克隆 我们应该能够识别出它们。

No presynaptic membrane proteins which anchor nerve terminals to the extracellular matrix (ECM) are known. The goal of my proposed research is to identify and characterize some of these proteins involved with anchoring nerve terminals. Such proteins could mediate the well-known trophic interactions between the nerve terminal and basal lamina during nerve regeneration. Of special interest, therefore, will be those proteins that are specific for a subgroup of synapses. We have identified a proteoglycan from elasmobranch electric organ which has some of the characteristics of such an anchoring protein. It is found on the nerve terminal surface restricted to the synaptic region. It is tightly bound to and enriched in an extracellular matrix (ECM) fraction. Intriguingly, this proteoglycan contains an antigenic determinant which is only associated with the electric organ neurons. Finally, synaptic vesicles also contain a transmembrane proteoglycan which shares this antigenic determinant. Thus, synaptic vesicles also might contain this same proteoglycan. From this data we hypothesize that this proteoglycan is presynaptic membrane protein which links the nerve terminal to the ECM. In addition, the synaptic vesicles may act as vehicles for shuttling this molecule to and from the nerve terminal surface. This research proposal has two basic goals: 1) to determine the validity of the above hypothesis; 2) to identify and characterize other presynaptic membrane proteins which anchor the synaptic ECM. To accomplish the first goal several steps are required. We will determine whether the proteoglycan is an integral membrane protein by the presence or absence of a hydrophobic tail. We will identify the ECM components which bind the proteoglycan. If the proteoglycan is an integral membrane protein and binds ECM components, it must link the nerve terminal to the matrix. If this linkage is through the pathway specific antigenic determinant, this linkage could be specific to this synapse. A biochemical comparison of the synaptic vesicle and ECM proteoglycan protein cores will determine whether these two molecules could share a precursor-product relationship. To achieve the second goal we will use the ECM fraction, in which the nerve terminal proteoglycan was originally found. We will isolate a subfraction containing the integral membrane proteins contained in this ECM material. If presynaptic membrane proteins (other than the proteoglycan) bind to the ECM, they should be present in this subfraction. By making monoclonal antibodies against this subfraction, we should be able to identify them.