The Role of Serine Protease Inhibitors in Nervous System Development

神经细胞在称为突触的特殊结构上相互通信。在突触处，细胞通过特殊的蛋白质相互连接，这些蛋白质的功能就像胶水一样。在发育过程中，有必要松开或修饰这些粘连蛋白，以便神经分支可以生长，新的连接可以建立。当形成新的记忆时，大脑中的一些突触也会发生类似的变化。黏附蛋白被称为蛋白酶的酶分解。这些酶是由神经细胞制造的，在突触处释放。释放的蛋白酶不会以不受控制的方式降解突触蛋白。取而代之的是，他们遇到了其他被称为“蛇毒”的蛋白质，这种蛋白质抑制了蛋白酶。因此，在丝氨酸水平较高的地区，蛋白酶活性会降低。蛇是由多种神经细胞组成的，无论是哺乳动物还是无脊椎动物。例如，人类大脑中最常见的丝蛋白(神经丝蛋白)与果蝇大脑中发现的丝蛋白密切相关，这种丝蛋白被称为Spn4。在这项研究中，PI将研究果蝇神经细胞和肌肉之间的突触。在这些突触中发现了Spn4，我们假设它抑制了参与突触正常发育的一种或多种蛋白酶。Spn4在神经肌肉突触的发育和功能中所起的作用将在蛋白质数量在发育过程中增加或减少的情况下进行研究。这个项目将研究神经系统活动如何通过各种基因突变影响Spn4的数量或功能。最后，PI将确定Spn4抑制的蛋白水解酶。拟议活动的更广泛影响：教育和外联。调查员有丰富的培训本科生、研究生和博士后研究员的经验，包括来自代表性不足的少数群体的成员(包括本提案中的一名研究生)。他鼓励本科生的研究，包括发表由之前的NSF资助的论文(1名本科生第一作者，1名合著者)。该项目将支持学生在细胞神经生物学、神经发育和遗传学领域的持续培训，为他们的高级科学职业生涯做好准备。研究社区：实验室开发的许多试剂和转基因株系具有广泛的实用价值，研究人员可以免费获得，进一步促进了科学研究。最后，关于控制突触发育和可塑性的分子和细胞机制的基础知识为开发未来普遍有益于社会的神经生物学应用提供了坚实的基础。

Nerve cells communicate with each other at specialized structures known as synapses. At the synapse cells are anchored to each other by specialized proteins that function like glues. During development it is necessary to unstick or modify these adhesive proteins, so that nerve branches can grow and new connections can be made. Similar changes occur at some synapses in the brain when new memories are formed.The adhesive proteins are broken down by enzymes known as proteases. The proteases are made by nerve cells and are released at the synapse. The released proteases do not degrade synaptic proteins in an uncontrolled fashion. Instead, they encounter other proteins known as "serpins", which inhibit the proteases. Thus, in areas where serpin levels are high, the protease activity is reduced. Serpins are made by many kinds of nerve cell, both in mammals and in invertebrates. For example, the most common serpin of the human brain (Neuroserpin) is closely related to the serpin found in the brain of the fruit fly Drosophila, known as Spn4. In this proposal the PI will examine the synapses made between nerve cells and muscles in Drosophila. Spn4 is found at these synapses, where we hypothesize that it inhibits one or more proteases involved in the normal development of the synapse.The role that the Spn4 plays in both the development and function of nerve-muscle synapses will be examined in situations where the amount of the protein is either increased or reduced during development. This project will examine how nervous system activity influences the amount or function of Spn4 using various genetic mutations. Finally, the PI will identify the proteases that are inhibited by Spn4. Broader Impacts of Proposed Activity: Education and outreach. The investigator has extensive experience training undergraduates, graduate students, and postdoctoral fellows, including members from underrepresented minority groups (including one graduate student in this proposal). He encourages undergraduate research, including publication of papers supported by the previous NSF funding (1 undergraduate first author, 1 coauthor). The project will support the continued training of students in the areas of cellular neurobiology, neural development, and genetics, preparing them for advanced scientific careers. Research community: Many of the reagents and transgenic lines developed in the lab are of widespread utility, and are freely available to researchers, furthering scientific inquiry. Finally, fundamental knowledge about the molecular and cellular mechanisms governing of synaptic development and plasticity provides a firm foundation for developing future neurobiological applications of general benefit to society.