2011-05-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/643456摘要：細胞中囊泡傳運(vcsicular trafficking)以及細胞骨架道組(cytoskclctal rearrangement) 會共同參與調控细胞週期進行、細胞生長、細胞分化、细胞極化、移動及遷移爬 行*這個過程中的其中-•個主要調控因子是Ras小GTP酶家族蛋白，他們藉由鳥苷 酸交換因子（guanine nucleotidc cxchangc factors (GEF))和 GTP酶活化蛋白（GTPasc activating proteins (GAP))調控，参與架構複雜的細胞訊息傳導"分析腫瘤發生過程 中，Ras小GTP酶蛋白的訊息傳導路徑發現，Ras蛋白發生突變或其調控因子GEF和 GAP失去調控，都會導致腫瘤發生。腺嘌呤核苷二磷酸核醣化因子蛋白(ADP-nbosylation factors (ARFs))廣於Ras小GTP酶蛋白家族，調控細胞膜運輸、維持胞器 健全、细胞膜脂質修飾和細胞骨架動力》ARF家族的蛋白，以及其G_GEF都被 認為和多種不同種類的癌症生成有關，如神經膠質瘤、黑色素瘤、肝癌、前列腺 癌、乳癌及大腸癌。許多硏究指出，ARF6組成的訊息傳導途徑和癌细胞的侵襲及 轉移有關《最近的硏究也發現，ARF6*GEF cytohesins和表皮細胞生長因子（EGF) 共同影響了 EGF接受器的活化程度，影響癌症的病理發展。ARLs(ARF-Likcs)和 ARFs有40 - 60%的氨基酸相似性，在真核物種的演化中高度相似》ARF-like GTPases包括三個相似分子：ARL4A，ARL4C，和ARL4D，表現在特定分化時期、 胚胎發育期和組織中。我們最近發表硏究顯示ARL4D可藉由Cytohcsin-2/ARNO路 徑，造成ARF6活化來調控細胞骨架的重組。我們最新的硏究結果驗證了數個 ARL4結合蛋白，功能上和表皮細胞癌化有關，包含胞膜接受器、磷酸酶、細胞骨 架蛋白和肌動蛋白結合蛋白、囊泡分類蛋白、細胞黏附分子，甚至包含其他small GTPases的調控者》現階段實驗我們進一步要證明，什麼訊息足以活化ARL4家族蛋 白和其下游，並參與與泡傳輸和細胞骨架的調控，以及他們在細胞膜接受器訊息傳 遞、細胞遷移、细胞侵襲和癌症生成的重要角色。在這個計畫中我們研究目標是：1.硏究ARL4GTPases訊息路徑在癌症發生過程的生理意義。2.探討ARL4GTPases訊息路徑對於癌症發生過程的生理機制。3.驗證探討ARL4 GTPases上游調控機制，用來建立藥物篩選平台，發展治療症 生成的ARL4 GTPases抑制劑《本硏究計畫具有發展的重要性：1.瞭解ARL4 GTPases在異泡傳輸及細胞骨架重組 的調控機制：2.幫助了解和執行ARL4 GTPases和其結合蛋白調控因子的生化和基 因操控應用。3•本研究幫助發展创新的ARL4 GTPases訊息調空分子，有益於理解 癌症病理發展，有益於發展創新的生物標記和治療藥物標的，獲得對於病人有效的診斷方式和治療方法。<br> Abstract: Vesicular trafficking and cytoskeletal rearrangement work in concert to control cell cycle progression,cell growth, differentiation, polarization, motility, and migration. One of the key regulators of theseprocesses are Ras superfamily small GTPases, which were regulated by their guanine nucleotideexchange factors (GEF) and GTPase activating proteins (GAP), constitute signaling cascades thatmodulate complex tasks in the cell. Characterization of signaling pathways of Ras family proteins inoncogenesis has revealed that direct mutational activation of small GTPases or the deregulation oftheir GEFs and GAPs could lead to oncogenesis.The ADP-ribosylation factors (ARFs) are Ras family small GTPases involved in membrane transport,maintenance of organelle integrity, membrane lipid modification, and cytoskeletal dynamics. Membersof ARF family as well as their GAPs and GEFs have been suggested to associate with the formationof different typecancers, such as glioma, melanoma, hepatocellular carcinoma, prostate cancer, breastcancer, and colorectal cancer. Several studies showed that ARF6 constituted a signaling pathwayinvolved in the tumor cell invasion and metastases. Recent study also showed that ARF6-GEFcytohesins and EGF concertedly determine the degree of EGFR activation and are relevant in thepathophysiology of certain cancers. ARLs share 40–60% amino acid sequence identity with ARFsand are highly conserved throughout eukaryotic evolution. The expression of three related ARF-likeGTPases, ARL4A, ARL4C, and ARL4D, is differentiation-dependent, developmentally regulated,and tissue specific. Our recent study showed that ARL4 acts as a novel upstream regulator ofcytohesin-2/ARNO to promote ARF6 activation and modulate actin remodeling and cell migration.Recently, we identified several ARL4-interacting proteins, whose functions have been associated withepithelial cell carcinogenesis, ranging from membrane receptors, kinases, microtubule- andactin-binding proteins, endosomal sorting proteins, adhesion molecules, to regulators of other smallGTPases. In this study, we would like to demonstrate that ARL4 family proteins are activated by yetto be identified signal(s) to recruit their effectors to participate in vesicular trafficking andcytoskeletal regulation, and thereby play important roles in receptor-mediated cell signalling, cellmigration and invasion, and/or tumorigenesis. The following studies are our goals in this proposal:1. To study the physiological roles of ARL4 GTPases signaling in oncogenesis process.2. To investigate mechanisms of ARL4 GTPases signaling in modulating oncogenesis process.3. To identify and characterize upstream regulators for ARL4 GTPases and establish a drug-screeningplatform for identification of ARL4 signaling inhibitors in oncogenesis.The proposed research is significant in that: 1) it will contribute to our understanding of theregulation of vesicular trafficking and cytoskeleton reorganization by ARL4 family smallGTPases; 2) it will provide the knowledge and the methods for biochemical and geneticmanipulation of the interaction of ARL4s and their associated molecules or regulators; and 3)the information gained will lead to the discovery of novel ARL4s signaling moleculescontributing to the pathogenesis of cancer, facilitate the identification of novel biomarkersand drug targets, yielding more effective diagnostic and treatment strategies for patients.鳥苷酸蛋白酶囊泡傳運細胞骨架重組癌症生成細胞移動