簡正鼎_2018_ Journal of Cell Biology

簡正鼎老師為本會會員，現任理事，任職於中央研究院分子生物研究所，其研究是利用果蠅的樹突分支神經細胞 (da neurons) 來做為研究樹突發育的模型。目前的研究主要是透過利用螢光影像技術和果蠅基因實驗來闡明這變化多端的細胞活動是如何進行，如高基氏體的動態表現、蛋白質醣基化及細胞細胞間的交互作用是如何影響果蠅樹突分支化。我們亦嘗試解答神經肌肉接合處 (neuromuscular junction, NMJ) 在果蠅的發育過程中是如何建立。

簡老師實驗室最近於Journal of Cell Biology 2018 發表 Actin blobs prefigure dendrite branching sites。謝謝老師與我們分享其成果：

Journal of Cell Biology 2018

神經元的樹突型態複雜，猶如大樹的分枝，功能上負責接收與整合外來訊號，與大腦的功能息息相關，大腦出現病變時如阿茲海默症，樹突型態也常出現異狀。樹突在生長時會不斷的長出新的分枝，分枝的密度恰好覆蓋所有的區域，但分枝之間需避免交錯，這與樹突分岔點的決定有關。肌動蛋白是細胞內重要的骨架成分，它在樹突內行成團狀(actin blobs)結構，不斷的巡邏移動，當肌動蛋白團停滯時，新的樹突會從停滯點行成，肌動蛋白會大量注入新的樹突，穩定其結構。這一新的樹突行成機制，可促進如痛覺神經元長出大型的樹突結構。本研究由TIGP-MCB 的國際學生Vanitha Nithianandam獨力在分子生物研究所簡正鼎博士實驗室完成，文章發表在Journal of Cell Biology.

Neuronal dendrites are complex in form, like the branches of large trees, and function in receiving and integrating external signals, which are indispensable to the brain function. In brain disorders such as Alzheimer's disease, the dendritic pattern often appears abnormal. During growth, dendrites continue to emanate new branches. The branches densely cover the innervating areas, but avoid crossovers, a process highly depending on branching point decision. Actin, the major cytoskeletal component in neurons, is highly dynamic. The “actin blobs” we found and named move and surveil continuously in dendrites. When an actin blob is stagnant, a new branch forms soon at the stagnation point, and the actin content infuses into the new branch, as a way to stabilize the structure. This new branching mechanism we found promotes the growth of large dendritic structures such as nociceptive neurons (responsible for pain sensation). The study was conducted by the international graduate student of TIGP-MCB, Vanitha Nithianandam, at the laboratory of Dr. Cheng-Ting Chien of the Institute of Molecular Biology. The article was published in the Journal of Cell Biology (2018).

(綠色螢光為移動中肌動蛋白團，痛覺神經元的樹突以紅色螢光標記)

原始文章：http://jcb.rupress.org/content/early/2018/07/23/jcb.201711136

簡正鼎老師實驗室網頁: http://www.imb.sinica.edu.tw/~ctchien/