与Sec23的顺序相互作用控制了囊泡流量的方向
Christopher Lord1, Deepali Bhandari, Shekar Menon
1Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California at San Diego, La Jolla, California 92093-0668, USA.
Nature
|May 3, 2011
概括
囊泡运输的定向性依赖于Sec23p/Sec24p层复合体. 戈尔吉相关的Hrr25p激酶化了外层,使囊泡融合成为可能,并确保了单向的ER-Golgi流量.
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:
- 囊泡流量的方向性对于细胞功能至关重要.
- 这种Sec23p/Sec24p外套复合体调解了从内质网膜 (ER) 发芽的囊泡.
- 涂层释放的精确机制及其与膜融合的关系仍然不清楚.
研究的目的:
- 研究Sec23p/Sec24p层复合体在ER-Golgi囊泡交通方向性中的作用.
- 确定调节外层释放和囊泡融合的因素和机制.
- 了解如何保持单向传输并防止反融合.
主要方法:
- 使用酵母运输试验追踪ER衍生的囊泡.
- 研究了外套组件和其他因素之间的蛋白质-蛋白质相互作用.
- 分析了戈尔吉关联酶Hrr25p在外套修饰中的作用.
主要成果:
- 来自ER的囊泡保留它们的外套,直到到达Golgi.
- 戈尔吉相关的Hrr25p酸化了Sec23p/Sec24p层复合体.
- 层酸化对于囊泡融合至关重要,而脱酸化则对于芽生长是必需的.
- Sec23p 顺序地与 TRAPPI 和 Hrr25p 相互作用,以确保定向流量.
结论:
- 在戈尔吉,Hrr25p的涂层酸化是ER-戈尔吉囊泡融合的关键步骤.
- Sec23p的顺序相互作用调节了囊泡运输的方向性.
- 这些机制保留在哺乳动物细胞中,突出显示了它们的基本重要性.
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...
Coat Assembly and GTPases
Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
Vesicular Tubular Clusters
After budding out from the ER membrane, some COPII vesicles lose their coat and fuse with one another to form larger vesicles and interconnected tubules called vesicular tubular clusters or VTCs. These clusters constitute a compartment at the ER-Golgi interface known as ERGIC (Endoplasmic Reticulum Golgi Intermediate Compartment). The ERGIC is a mobile membrane-bound cargo transport system that sorts proteins secreted from ER and delivers them to the Golgi.
With the help of motor proteins such...
With the help of motor proteins such...
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...
Pinching-off of Coated Vesicles
Vesicle budding is orchestrated by distinct cytosolic proteins such as adaptor proteins, coat proteins, and GTPases. To initiate vesicle budding, membrane-bending proteins containing crescent-shaped BAR domains bind to the lipid heads in the bilayer and distort the membrane to form a protein-coated vesicle bud. Adaptors proteins such as AP2 for clathrin-coated vesicles can nucleate on the deformed membrane. Finally, coat proteins such as clathrin or COPI and COPII assemble into a coat forming...
Fusion of Secretory Vesicles with the Plasma Membrane
Proteins and neurotransmitters in secretory vesicles can be released from a cell upon vesicle docking, priming, and fusion with the plasma membrane. Vesicles are docked and primed in preparation for the quick exocytosis of their contents in response to a stimulus. The fusion process is mainly carried out by a SNAP Receptor or SNARE complex, consisting of synaptobrevin, syntaxin-1, and SNAP-25.
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...


