Mechanism for the Organization of the Golgi apparatus

高尔基体的组织机制

• 批准号: 11480183
• 负责人: TAGAYA Mitsuo
• 金额: $ 8.9万
• 依托单位: Tokyo University of Pharmacy & Life Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11480183/
• 关键词: Golgi apparatus; retrograde transport; trimeric GTP-binding protein; endoplasmic reticulum; ceramide; phospholipase; membrane fusion; 膜融合syntaxin

The Golgi apparatus consisting of stacks of cisternae is a station for the transit of secretory proteins. Membranes flow into and out from the Golgi apparatus as secretary proteins are transported from the endoplasmic reticulum to the plasma membrane through this organelle. In addition, membrane efflux occurs in accordance with retrograde transport from the Golgi to the endoplasmic reticulum. In spite of massive membrane flow, the structure of the Golgi apparatus is maintained during the interphase of mammalian cells. The purpose of the present project is to elucidate the mechanism of the organization of the Golgi apparatus, and to identify new proteins involved in vesicular transport in the early secretory pathway. The following results were obtained.1. Nordihydroguaiaretic acid-induced Golgi disassembly was prevented by overexpression of Gαi2 or Gαz, but not other Gα species. Expression of RGS (regulator of G-protein signaling) proteins specific for Gαz also caused Golgi disassembly, suggesting that the active form of Gαz plays a role in the maintenance of the Golgi apparatus.2. Short chain ceramide blocked Golgi disassembly caused by Golgi-disrupting reagents such as brefeldin A, whereas long chain ceramide enhanced their effects. This suggests that sphingolipid metabolism is implicated in the stability of the Golgi apparatus.3. A novel protein termed p125 that can interact with a subunit of COPII, Sec23p, was isolated. It possesses a Pro-rich region and a phospholipase A domain. p125 was colocalized with a tethering protein, p115. A data base search revealed the presence of a protein (KIAA0725p) which shows high similarity to p125.4. A novel syntaxin species (syntaxin 18) localized in the endoplasmic reticulum was identified. Syntaxin 18 is possibly involved in the retrograde transport. Several syntaxin 18-binding proteins were identified and their characterization is now in progress.

高尔基体由成堆的脑池组成，是分泌蛋白质的中转站。当分泌蛋白从内质网通过这个细胞器输送到质膜时，膜从高尔基体流入和流出。此外，从高尔基体到内质网的逆行转运过程中也会发生膜外流。尽管有大量的膜流动，高尔基体的结构在哺乳动物细胞的间期保持不变。本项目的目的是阐明高尔基体的组织机制，并鉴定早期分泌途径中参与囊泡运输的新蛋白。取得了以下研究成果：1.去甲二氢愈创木酸诱导的高尔基体解离可通过过表达Gαi2或Gαz来阻止，但不能阻止其他Gα物种的过度表达。结论1.G-αz的活性形式在高尔基体的维持中起重要作用，G-αz的活性形式在高尔基体的维持中起作用。短链神经酰胺可阻断诸如布雷菲尔丁A等高尔基体干扰试剂引起的高尔基体拆解，而长链神经酰胺则增强了它们的作用。这表明鞘磷脂代谢与高尔基体的稳定性有关。分离到一种新的能与COPII亚单位Sec23p相互作用的蛋白p125。它具有一个富含Pro的区域和一个磷脂酶A结构域。P125与系留蛋白p115共定位。数据库搜索显示存在一个与p125.4高度相似的蛋白质(KIAA0725p)。鉴定了位于内质网中的一种新的合成素物种--合成素18。Synaxin 18可能参与逆行转运。已经鉴定了几个Synaxin 18结合蛋白，它们的特征目前正在进行中。

项目成果

Kuroiwa,K. et al.: "Arachidonyltrifluoromethy ketone, a phospholipase A_2 antagonist, induces dispersal of both Golgi stack-and trans Golgi network-resident proteins throughout the cytoplasm."Biochem.Biophys.Res.Commun.. 281. 582-588 (2000)

黑岩，K.

Mizoguchi,T. et al.: "Determination of functional regions of p125, a novel mammalian Sec23p-interacting protein."Biochem.Biophys.Res.Commun.. 279. 144-149 (2000)

沟口，T.

Yamaguchi,T.et al.: "Regulation of the Golgi structure by the a-subunits of heterotrimeric G proteins"FEBS Lett.. (in press).

Yamaguchi,T.et al.：“异源三聚体 G 蛋白的 a 亚基对高尔基体结构的调节”FEBS Lett..（出版中）。

Tani, K.et al.: "p125 is a novel mammalian Sec23p-interacting protein with structural similarity to phospholipid-modifying proteins."J.Biol.Chem.. 274. 20505-50512 (1999)

Tani, K. 等人：“p125 是一种新型哺乳动物 Sec23p 相互作用蛋白，其结构与磷脂修饰蛋白相似。”J.Biol.Chem.. 274. 20505-50512 (1999)

Tani,K.et al.: "p125 is a novel mammalian Sec23p-interacting protein with structural similarity"J.Biol.Chem.. 274. 20505-20512 (1999)

Tani,K.等人：“p125 是一种结构相似的新型哺乳动物 Sec23p 相互作用蛋白”J.Biol.Chem.. 274. 20505-20512 (1999)