Membrane-Transport Signaling Involving the GTPase Cycle of G proteins

涉及 G 蛋白 GTP 酶循环的膜运输信号转导

基本信息

批准号：
18207008
负责人：
KATADA Toshiaki
金额：
$ 31.87万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-18207008/
关键词：
Signal transduction Protein Gene Genome project G protein GTPase cycle

项目摘要

G proteins, which cycle between the two different conformations of GTP- and GDP-bound states, play important roles as a "molecular switch" in many intracellular signaling pathways. The G protein families include 1) translation factors involved in protein synthesis and mRNA degradation, 2) trimeric G proteins, and 3) small GTPases. The small GTPases, such as Ras, Rab, Arf, and Rho/Rac family, are involved in the regulation of cell growth and differentiation, intracellular vesicle trafficking, and cell shape and adhesion. However, there are still many other small GTPases, of which functions are unknown. In this study, we have identified and characterized novel small GTPases exhibiting unique biochemical properties or tissue expression.1. The Arl8 GTPase was essential for lysosome biogenesis in the macrophage-like coelomocytes of C. elegans: ARL-8 localized primarily to lysosomes, and a deletion mutant of arl-8 displayed an increase in number of lysosomes that were small in size and non-a … More cidic. Extracellular macromolecules were endocytosed and transported through endosomes in arl-8 mutant coelomocytes, but its degradation was markedly reduced. Thus, Arl8 appeared to function as an important regulator of lysosome biogenesis/function.2. Rab45 is an atypical GTPase that contains a coiled-coil motif at the mid region and a distinct N-terminal EF-hand domain with C-terminal Rab-homology domain. Rab45 was capable of self-interacting, and the self-interaction required the mid region containing the coiled-coil motif. Rab45 expressed in HeLa cells was localized in a small patch in the perinuclear area of the cell, and the localization was regulated by the guanine nucleotide-bound states of Rab45. The mid region, together with Rab domain, appeared to be essential for the characteristic perinuclear localization of Rab45.3. Di-Ras, which belongs to a distinct branch of the Ras family, existed predominantly as a GTP-bound form in living cells. The expression of Di-Ras was rather specific in neuronal cells, and its over-expression induced apoptotic cell death with DNA fragmentation in neuronal cells. A deletion mutant of arl-8 in C. elegans displayed a phenotype that acetylcholine release from nerve cells might be impaired. Less

G蛋白在GTP和GDP结合状态的两个不同考虑之间循环循环，在许多细胞内信号通路中起着重要的作用，作为“分子开关”的重要作用。 G蛋白家族包括1）涉及蛋白质合成和mRNA降解的翻译因子，2）三聚体G蛋白和3）小GTPase。小的GTPases（例如RAS，RAB，ARF和RHO/RAC家族）参与细胞生长和分化，细胞内囊泡运输以及细胞形状和粘合剂的调节。但是，仍然还有许多其他小型GTPase，其中哪些功能尚不清楚。在这项研究中，我们确定并表征了具有独特生化特性或组织表达的新型小GTP酶。1。 ARL8 GTPase对于秀丽隐杆线虫的巨噬细胞样片状细胞中的溶酶体生物发生至关重要：ARL-8局部原发性至溶酶体，ARL-8的缺失突变体显示出大小和非A的溶酶体数量增加的溶酶体数量增加。细胞外大分子被内吞并通过ARL-8突变型核细胞中的内体运输，但其降解显着降低。那就是ARL8似乎是溶酶体生物发生/功能的重要调节剂2。 RAB45是一种非典型GTPase，在中部区域中包含一个盘绕螺旋的基序，并且具有C末端Rab-andomology域的独特的N末端EF手域。 Rab45能够进行自我交互，自我相互作用需要包含盘绕圈图案的中部区域。在HeLa细胞中表达的RAB45位于细胞核周区域的一个小斑块中，并且由Rab45的鸟嘌呤核结合状态调节定位。中部区域与RAB结构域一起似乎对于Rab45.3的特征性核周定位至关重要。 Di-Ras属于RAS家族的不同分支，主要作为活细胞中的GTP结合形式存在。 DI-RAS的表达在神经元细胞中相当具体，其过表达诱导的凋亡细胞死亡在神经元细胞中伴有DNA碎片。秀丽隐杆线虫中ARL-8的缺失突变体显示出一种表型，即乙酰胆碱从神经细胞中释放可能受到损害。较少的