someAmphiphilicMolecules, such as many natural syntheticsurface active agent And cannot be simply synthesizedMicellePhospholipids with a closed double-layer structure will spontaneously form when dispersed in waterMolecular ordered combination, called vesicles, also calledLiposome(liposome) 。The meanings of the terms vesicle and liposome are somewhat ambiguous in the literature.It is generally believed that if theseAmphiphileyesNatural surfactantlecithin, the structure formed is called liposome;If it is composed of synthetic surfactant, it is called vesicle.Therefore, the vesicleSecretory proteinIt plays an important role as a transport carrier in the discharge process.
It is used in some cells to store, transport and digest cell products and wastes.
Application of vesicles
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One of the most important applications of vesicles is to simulate biofilms.The main body of biomembrane is a closed bilayer vesicle structure composed of phospholipids and proteins arranged directionally.Biofilm plays a very important role in living organisms, with ion migrationImmune recognitionAnd other functions.The study of vesicles can deepen people's understanding of biomembrane and provide a new way for people's bionic research.
Another important application of vesicles is as drug carriers.Compared with other microstructures, vesicles have unique structures, that is, there are hydrophilic and hydrophobic micro regions, which enables vesicles to carry both water-soluble and water-insoluble drugs.At the same time, the vesicle has a double-layer membrane structure, which has good compatibility with biomembrane, and is an ideal carrier for drugs in vivo.Because it takes a long time for molecules to enter and exit the vesicles, in recent years, people have studied using vesicles asSlow release agentIn order to give better play to the efficacy.
In recent years, with the development of nanotechnology, people also use vesicles as templates to prepare nanomaterials.Vesicles can also provide a suitable microenvironment for some chemical and biochemical reactions.In addition, vesicles are used in cosmetics industry andfood industryIt also has certain applications.
Vesicular transport mechanism
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The normal operation of cells in an organism depends on the right molecules arriving at the right place at the right time.Some molecules, such as insulin, need to be transported outside the cell, while others need to be transported inside the cell.The molecules generated inside the cell are wrapped in vesicles (shown in blue in the figure), but how do these vesicles achieve this precise transport?This has not been understood.
Randy W. Schekman found that proteins under gene control play an important role in this vesicle transport mechanism.As shown in the figure here, by comparing normal yeast cells (left) with cells with transport mechanism defects (right), he successfully identified the genes that control this transport process.
James E. Rothman found that a protein compound (orange in the figure) can make the vesicles fuse with the target cell membrane.The protein material on the vesicle will bind to the specific protein on the target cell membrane, so that the vesicle can release the special "molecular goods" it carries in the right position.
Thomas C. S ü dhof studied how nerve cells in the brain transmit signals to each other, andcalcium ionThe role played in this process.He identified a molecular mechanism (shown in purple in the figure) that can react to incoming calcium ions and trigger vesicular fusion, thus explaining how the accuracy of time in vesicular transport mechanism is achieved and what it carriesSignal moleculeHow can substances be released under control.
On October 7, according to the official website of the Nobel Prize, 2013Nobel Prize in Physiology or Medicine It was announced today that James E. Rothman was the winner,Randy W. Schekman&Thomas C. S ü dhof, won the award for their discovery of the mystery of intracellular transport mechanism.
Every cell in an organism is a factory for producing and exporting molecules.For example, insulin is produced here and released into the blood, and neurotransmitters are transmitted from one nerve cell to another.These molecules are delivered in the form of "packets" in cells, which are called "cell vesicles".The three award-winning scientists discovered the molecular mechanism of how these "packets" are transported to the right place at the right time.
Randy Schekman found a series of genes related to vesicle transport mechanism;James Rothman discovered the protein mechanism that allows these vesicles to fuse with their targets, so as to realize the transmission of the "goods" transported;Thomas S ü dhof revealed how the signal controls the vesicles so that they can accurately distribute the "goods" they carry.
In the process of this discovery, three scientists: Rothman,Schekman and S ü dhof revealed the fine structure and control mechanism of intracellular transport system.Of this systemDestabilizationWill lead to harmful results, such as nervous system diseases, diabetes orImmune system disorder。[1]
