EXTRACELLULAR MATRIX NERVE TERMINAL ANCHORAGE PROTEIN

细胞外基质神经末梢锚定蛋白

基本信息

批准号：
2609590
负责人：
STEVEN Scott CARLSON
金额：
$ 18.4万
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 1999-11-30
项目状态：
已结题

项目摘要

During nerve regeneration, extracellular matrix (ECM) directs the rebuilding of the neuromuscular junction. Active zones for neurotransmitter release in the presynaptic plasma membrane appear to be rebuilt following cues of the synaptic ECM. Presumably, transmembrane nerve terminal ECM receptors (nerve terminal anchorage proteins) bind these synaptic ECM cues and form a link to the cytosolic, exocytotic machinery of the nerve terminal. We have identified a potential nerve terminal ECM receptor, a protein complex of 4 proteins and a transmembrane proteoglycan, SV2pg. We call this protein complex the SV2pg complex. The SV2pg complex is a component of the synaptic vesicle membrane and has the properties expected of an ECM receptor. 1) In addition to being part of the synaptic vesicle, this complex is found on the nerve terminal surface in the presynaptic plasma membrane. 2) Subcellular fractionation of electric organ demonstrates that, although most SV2pg is in synaptic vesicles, a significant amount is tightly bound to ECM. 3) We find that the purified SV2pg complex binds to a component of the electric organ ECM extracts. 4) The SV2pg complex binds to laminin. Laminin is a known component of the synaptic ECM and is abundant in electric organ ECM extracts. We propose to test the hypothesis that the SV2pg complex acts as an ECM receptor on the nerve terminal surface: l) We will fully characterize the SV2pg complex and determine how to isolate the components from one another. 2) We will determine whether the SV2pg becomes tightly associated with synaptic ECM during synaptogenesis at the neuromuscular junction. 3) We will determine whether we can block this association during synaptogenesis with antibodies to the SV2pg complex and look at the effects of this blockage on the resulting synaptic structure. 4) We will attempt to isolate the ECM ligand for the SV2pg complex and determine which component of the complex binds the ligand. As mentioned above, this ligand may be laminin. From successful completion of our research we hope to gain some understanding of the molecular events involved in building the synapse during synaptogenesis. In addition, since the SV2pg complex is a synaptic vesicle component and perhaps an ECM receptor, we may elucidate an activity-dependent adhesion mechanism of the synapse.

在神经再生过程中，细胞外基质（ECM）指导神经肌肉接头的重建。活动区域突触前质膜中的神经递质释放似乎是根据突触 ECM 的提示进行重建。推测是跨膜神经末梢 ECM 受体（神经末梢锚定蛋白）结合这些突触 ECM 信号并形成与胞质、胞吐神经末梢的机械。我们已经确定了潜在的神经末端 ECM 受体，由 4 种蛋白质和跨膜蛋白组成的蛋白质复合物蛋白多糖，SV2pg。我们将这种蛋白质复合物称为 SV2pg 复合物。 SV2pg 复合体是突触小泡膜的组成部分，具有 ECM 受体的预期特性。 1）除了成为一部分突触小泡的复合体位于神经末梢突触前质膜表面。 2) 亚细胞分级电器官的研究表明，尽管大多数 SV2pg 处于突触囊泡中，大量与 ECM 紧密结合。 3）我们发现纯化的 SV2pg 复合物与电子器官 ECM 的成分结合提取物。 4) SV2pg 复合物与层粘连蛋白结合。层粘连蛋白是一种已知的突触 ECM 的组成部分，在电器官 ECM 中含量丰富提取物。我们建议检验 SV2pg 复合体充当 ECM 的假设神经末梢表面的受体：l) 我们将充分表征 SV2pg 复杂并确定如何将组件从一个组件中分离出来其他。 2) 我们将确定SV2pg是否变得紧密关联神经肌肉接头突触发生期间的突触 ECM。 3）我们将决定是否可以在期间阻止此关联使用 SV2pg 复合物的抗体进行突触发生，并观察这种阻塞对所产生的突触结构的影响。 4）我们会尝试分离 SV2pg 复合物的 ECM 配体并确定复合物的哪个成分与配体结合。如上所述，这配体可以是层粘连蛋白。通过成功完成我们的研究，我们希望获得一些了解构建突触所涉及的分子事件在突触发生期间。此外，由于 SV2pg 复合体是一个突触囊泡成分，也许还有 ECM 受体，我们可以阐明突触的活动依赖性粘附机制。