2018-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/703987摘要：神經突觸形成對於神經功能至關重要，神經突觸組成需要活化區蛋白與突觸小泡等前突觸成員，而這些前突觸成員由神經細胞本體製造出來後由主動運輸系統導向到突觸位置。然而，我們對於細胞訊息分子如何調控突觸蛋白的標的導向機制所知甚少。我們的初期研究顯示Galpha蛋白藉由adenylyl cyclase製造cAMP活化PKA後導致突觸數目減少而且使突觸小泡錯誤地導向至樹突處。我們進一步發現PKA與活化區蛋白UNC-18在同一路徑上調控觸蛋白的標的導向。我們假設UNC-18可能是固定突觸分子的定錨因子，而cAMP可能作為促使前突觸成員離開突觸的釋放訊號。同時，我們的初步結果亦顯示CaMKII/UNC-43 可能傳遞著卸載突觸貨物的卸載訊號。在本計畫中，我們將使用一系列的分子標記來觀察PKA與CaMKII對於神經發育的影響，我們將分析軸突與樹突的特化、微管極化、與突觸的結構。我們將用即時攝影與光褪色處理來觀察PKA與CaMKII對於運輸方向與運輸卸載的調控。藉由遺傳篩檢與候選物分析，我們將系統性地找出固定突觸分子的定錨因子。總體而言，本計畫將幫助我們了解導向突觸分子的調控機制與突觸形成的基本原理。由於突觸形成的缺陷與神經退化疾病及精神疾病密切相關。本研究將幫助我們了解與對抗這些疾病。<br> Abstract: Synapse formation is critical for neuronal function that requires assembly of presynaptic components including active zone proteins and synaptic vesicles, which are manufactured in cell body and targeted to synaptic apparatus by active transport systems. However, we know very little about how synaptic targeting to presynaptic boutons is regulated by cell signaling pathways. Our preliminary studies showed that Galpha subunit likely induces cAMP production by adenylyl cyclase to reduce axonal synapse number through PKA activity and cause synaptic vesicles targeted to dendrites. We further found that PKA regulates synaptic targeting in the same pathway with an active zone protein UNC-18. We hypothesized that UNC-18 acts as “synaptic anchoring factor” that keeps presynaptic components in presynaptic boutons and cAMP may acts as a “release signal” that tell presynaptic components to leave presynaptic boutons through retrograde transport. Meanwhile, our preliminary results showed that CaMKII/UNC-43 likely mediates a “unloading signal” that promotes synaptic cargo deposit to presynaptic boutons. We will adopt molecular markers that reveals axon/dendrite specificity, microtubule polarity, and synaptic structures to understand the effect of PKA and CaMKII signaling on neuronal development. Grounded on our preliminary studies, our real-time recording and photobleaching experiments will further show the detail mechanism of how PKA and CaMKII signaling controls the active transport system in the directional preference and the loading/unloading choice. Furthermore, our candidate search and genetic screen will systematically identify novel anchoring factors that tether synaptic components in presynaptic boutons. Taken all together, this work will manifest the regulatory mechanism of synaptic targeting and synapse formation. Defects in synapse formation are implicated in neural psychiatric diseases and neurodegeneration disorders including schizophrenia, autism, and dementia. The work of this project will reveal insights to understand basics of these diseases and develop potential treatments.突觸形成主動運輸突觸運輸導向PCT-1PKACaMKIIsynapse formationactive transportsynaptic targetingPCT-1PKACaMKII