对于NSF,SNAP和Rab蛋白在MDCK细胞的顶端和底侧运输中的不同要求
E Ikonen1, M Tagaya, O Ullrich
1Cell Biology Programme, European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
Cell
|May 19, 1995
概括
这项研究揭示了表皮细胞运输通路的独特分子机制. 底侧运输使用Rab-NSF-SNAP-SNARE机制,而顶端运输使用不同的组件.
科学领域:
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
- 膜贩卖 膜贩卖 膜贩卖
背景情况:
- 两极化的上皮细胞表现出明显的顶端和底侧膜域.
- 了解控制极化膜运输的分子机制对于细胞功能至关重要.
研究的目的:
- 调查NSF,SNAP,SNAREs和Rab蛋白在上皮细胞中极化膜传输中的作用.
- 为了区分涉及到顶峰与底侧运输通路的分子机械.
主要方法:
- 采用了体外系统,使用了链条素O-透化马丁-达比犬 (MDCK) 细胞.
- 评估了对NSF,α-SNAP,Rab-GDI和神经毒素的抗体对TGN到血膜传输的影响.
主要成果:
- 来自跨戈尔吉网络 (TGN) 的基底侧运输被反NSF抗体抑制,并被alpha-SNAP刺激.
- 来自TGN的顶端传输不受反NSF抗体或α-SNAP的影响.
- 上运输对Rab-GDI和破伤风/肉毒神经毒素不敏感,这些神经毒素会抑制底侧运输.
结论:
- 拉布-NSF-SNAP-SNARE机制特别涉及到底侧膜传输.
- 独特的分子机械介导囊泡输送到顶端细胞表面.
- 这项研究阐明了极化膜贩运路径的特定分子要求.
相关概念视频
Overview of Secretory Vesicles
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Overview of Protein Sorting and Transport
Eukaryotic cells have different membrane-bound organelles with distinct protein requirements. The process by which proteins are targeted to a specific organelle is called protein sorting.
Protein sorting can be of two types: signal-based sorting and vesicle-based trafficking. In signal-based sorting, specific amino acid sequences called sorting signals target proteins to the proper location inside the cell either via gated transport or by protein translocation. In gated transport, folded...
Protein sorting can be of two types: signal-based sorting and vesicle-based trafficking. In signal-based sorting, specific amino acid sequences called sorting signals target proteins to the proper location inside the cell either via gated transport or by protein translocation. In gated transport, folded...
Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
SNAREs and Membrane Fusion
Once a transport vesicle has recognized its target organelle, the vesicular membrane needs to fuse with the target membrane to unload the cargo. Transmembrane proteins called SNAREs present on organelle membranes and their vesicles, mediate vesicle fusion.
SNAREs exist in pairs that symmetrically interact and catalyze the fusion of the lipid bilayers in vesicle and target organelle. v-SNARE in the vesicle membrane are single polypeptide chains that bind to a complementary t-SNARE, composed of 2...
SNAREs exist in pairs that symmetrically interact and catalyze the fusion of the lipid bilayers in vesicle and target organelle. v-SNARE in the vesicle membrane are single polypeptide chains that bind to a complementary t-SNARE, composed of 2...
Protein Translocation Machinery on the ER Membrane
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Rab Cascades
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.


