EXTRACELLULAR MATRIX NERVE TERMINAL ANCHORAGE PROTEINS

细胞外基质神经末梢锚定蛋白

基本信息

批准号：
3404642
负责人：
STEVEN Scott CARLSON
金额：
$ 15.99万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
1985
资助国家：
美国
起止时间：
1985-07-01 至 1993-06-30
项目状态：
已结题

项目摘要

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.

没有突触前膜蛋白将神经末梢锚定在细胞外基质(ECM)是已知的。我提议的研究目标是识别和表征其中一些与锚定相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神经末梢和基底层之间的相互作用再生。因此，特别令人感兴趣的是那些能够特定于突触子群。我们从软骨鱼电器官中鉴定出一种蛋白多糖，具有此类锚定蛋白的一些特征。被发现了位于仅限于突触区域的神经末梢表面。这是与细胞外基质 (ECM) 组分紧密结合并富集。有趣的是，这种蛋白多糖含有一个抗原决定簇，它是仅与电器官神经元相关。最后，突触囊泡还含有跨膜蛋白聚糖，它具有这种特性抗原决定簇。因此，突触小泡也可能含有这种相同的蛋白多糖。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，突触小泡可能充当将该分子穿梭到以及来自神经末梢表面。该研究计划有两个基本目标：1）确定有效性上述假设； 2）识别和表征其他突触前锚定突触 ECM 的膜蛋白。为了实现第一个目标，需要采取几个步骤。我们将确定蛋白多糖是否是完整的膜蛋白不存在疏水性尾部。我们将确定 ECM 组件结合蛋白多糖。如果蛋白多糖是完整的膜蛋白并结合 ECM 成分，它必须将神经末梢与基质连接起来。如果这种联系是通过途径特异性抗原决定簇进行的，则该连接可能特定于该突触。生化比较突触小泡和 ECM 蛋白聚糖蛋白核心将决定是否这两个分子可能具有前体-产物关系。到实现第二个目标，我们将使用 ECM 部分，其中神经最初发现末端蛋白多糖。我们将分离出一个亚分数含有该 ECM 材料中所含的完整膜蛋白。如果突触前膜蛋白（蛋白多糖除外）与突触前膜蛋白结合 ECM，它们应该存在于这个亚组分中。通过制作单克隆针对这个亚组分的抗体，我们应该能够识别它们。