概括
研究人员研究了大鼠肝脏显微体中的酸丁胆运输. 他们发现了一种蛋白质载体或"翻转酶"的证据,可以促进脂在膜上的移动.
科学领域:
- 生物化学 生物化学
- 细胞生物学 细胞生物学
- 膜运输 运输 膜运输
背景情况:
- 脂在细胞质内网膜的细胞质侧进行合成.
- 脂双层组装需要向光质侧移动.
- 自发的跨膜脂运动是有限的.
研究的目的:
- 为了测试大鼠肝脏显微体中酸丁胆的蛋白质载体 (flippase) 假设.
- 为了研究氨酸胆转位的机制.
主要方法:
- 使用的 sn-1,2,-dibutyroylphosphatidylcholine (diC4PC),是一种可溶性酸胆类似物.
- 测量 diC4PC 传输到微小体囊泡的光区.
- 评估了运输动力学,类似物抑制和化学处理的影响.
主要成果:
- DiC4PC进入了微小体囊泡的光区.
- 运输是可和的,并且取决于时间,显微体和膜完整性.
- 运输被结构类似物和蛋白酶/化学处理抑制,这表明蛋白质介导.
- DiC4PC并没有通过对照囊泡或红细胞膜进行传输.
结论:
- 鼠肝显微体具有通过蛋白质介导的系统来转移脂胆.
- 这种翻转酶活动是特定的,对于脂双层的形成至关重要.
相关概念视频
Introduction to Membrane Traffic
The ER, Golgi apparatus, endosomes, and lysosomes work in tandem to modify, sort, and package proteins and lipids. An integrated membrane trafficking network facilitates the back and forth shuttling of molecules within different organelles in the same cell or across the cell membrane.
The transport of soluble and membrane proteins is mediated by transport vesicles that collect cargo from one cellular compartment and deliver it to another by fusing with the target organelle membrane. The Rab...
The transport of soluble and membrane proteins is mediated by transport vesicles that collect cargo from one cellular compartment and deliver it to another by fusing with the target organelle membrane. The Rab...
Synthesis of Phosphatidylcholine in the ER Membrane
The ER synthesizes lipids for building cell membranes and performing cellular functions such as energy storage and signaling. The lipid synthesis machinery embedded in the ER membrane primarily collects all reactants from the cytosol. Following synthesis, the secretory pathway and the ER contact sites distribute these lipids to other cellular organelles. Additionally, the energy-rich triacylglycerides are transported from the ER via lipid droplets.
The major components of all eukaryotic cell...
The major components of all eukaryotic cell...
Assembly of the Lipid Bilayer in the ER
Biological membranes are more than just a barrier separating cell cytoplasm from the outside environment. They are highly dynamic and help maintain the integrity and physiological stability of the cells as well as membrane-bound organelles. Membranes also play vital roles in cell-to-cell and intracellular communication.
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
A large chunk of any biological membrane is composed of phospholipids. These lipids have a heterogeneous distribution across different subcellular organelles and even between...
Membrane Asymmetry Regulating Transporters
Enzymes like flippase, floppase, and scramblase transfer phospholipids from one layer to another in the membrane, thereby affecting membrane asymmetry.
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
Flippase
Eukaryotic flippases are type-IV P-type ATPases or P4-ATPases belonging to P-type ATPase family proteins that are membrane-bound pumps involved in the ATP-mediated transport of ions and molecules across the membrane. Flippases flip specific phospholipids from the outer to the inner leaflet of a membrane. All P4-ATPases have one...
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.
Clathrin Coated Vesicles
Clathrin-coated vesicles use endocytosis to transport receptors and lysosomal hydrolases from the Golgi to the lysosome in the late secretory pathway. Clathrin-mediated endocytosis was the first described endocytic process, and Clathrin-coated vesicles remain one of the most well-studied transport vesicles. The molecular machinery that generates clathrin-coated vesicles comprises over 50 proteins that precisely coordinate vesicle formation. Cell surface receptors concentrated in indented sites...


