In Cell Biology, What Are Vesicles?

The mechanism of vesicle transport regulation refers to that certain molecules and substances cannot directly pass through the cell membrane, but rely on the vesicles surrounding the cell membrane for transport. The vesicles are fused with the target cell membrane, which can precisely control the proper time and position of the transmission of molecules such as hormones, biological enzymes and neurotransmitters under the instruction of nerve cells. The field of vesicle transport research has won the Nobel Prize in Physiology or Medicine in 1974, 1985, 1999, and 2013.

Vesicle transport regulation mechanism

The so-called vesicle transport regulation mechanism refers to that certain molecules and substances cannot directly pass through the cell membrane, but rely on the vesicles surrounding the cell membrane for transmission and transport. The vesicles are fused with the target cell membrane, which can precisely control the proper time and position of the transmission of molecules such as hormones, biological enzymes and neurotransmitters under the instruction of nerve cells. For example, insulin, which plays an important role in controlling blood sugar, is precisely delivered by vesicles and finally released into the blood. [1]

Biofilms constitute a natural barrier between cells and organelles, enabling some important life activities to be carried out in relatively independent spaces, thereby creating a process of the exchange of matter, energy and information between cells and organelles. The transport of materials (such as proteins and lipids) between membranous organelles in cells is mainly accomplished through vesicles.

Vesicle transport is both a basic process of life activity and an extremely complex dynamic process, especially in higher eukaryotes, involving many types of proteins and regulatory factors.

Vesicle transport generally includes processes such as budding, anchoring, and fusion, which require the participation of cargo molecules, transport complexes, dyneins, and microtubules, as well as the regulation of multiple molecules. The intracellular vesicle transportation system is just like a city's transportation system. Various vehicles (ie, transport complexes) with power (ie, dynein) are loaded with different goods (ie, cargo molecules on the vesicle). ), After arriving at the destination according to the designated driving route (ie, microtubules), the cargo is unloaded. Good traffic conditions in a city require fine traffic control (ie, regulatory molecules). If it is not well controlled, there will be traffic congestion in some places, and in severe cases, the entire city will be paralyzed. When similar conditions occur in our cells, these cells can no longer function normally and may even die.

Vesicle transport is a material transport method that all cells have. Nerve cells are the most representative of vesicle transport research, mainly because nerve cells have a special type of vesicle (synaptic vesicle), which participates in The release of neurotransmitters.

Existing research shows that there may be a set of instructions in the cell that precisely regulate the sorting and transportation of goods. It consists of cargo molecules, transport complexes, dyneins, transport tracks and related regulatory factors, which is called the "transport code." Decoding this set of instructions is critical to understanding cell function and vitality. This depends on the interdisciplinary (such as physics, chemistry, biology, etc.) and the development of new technologies (such as the new generation of microscopic imaging technology) to achieve real-time and long-term monitoring of intracellular vesicle transport.

In traditional cell biology, descriptions of various organelles are often based on static structures. With the development of live cell imaging, ultra-high resolution microscopy imaging and other technologies in recent years, people's understanding of organelles has risen to a dynamic level, that is, although various types of organelles are restricted to specific regions to complete certain physiological processes of cells, Function, but also continuous material exchange between organelles to ensure the steady state of organelles and perform their normal functions. Therefore, the basic scientific problem faced by cell biologists is: how exactly are the tens of thousands of goods transported by vesicles in the cell labeled and identified, and then accurately transported to a specific location and unloaded? (That is, how the vesicle transport process is finely regulated and methodically performed). In addition, once the transportation process is disrupted, what are the consequences for the cells?

The elucidation of intracellular vesicle transport mechanism is the basis for understanding the function of cells. This discovery will lead to a more dynamic understanding of cells and their functions. "Life is movement". Without vesicle transport, there is no vitality of cells and no vitality. If a city lacks a transportation system, it is a dead city; if a cell lacks a vesicle transportation system, it is nothing more than a "dead" cell, which is the static cell we usually see in pictures. On the basis of decoding the DNA code, scientists have developed technical methods such as proteomics and epigenomics, and have a better understanding of the functions of the full set of proteins encoded by the genome and their interaction and regulation laws, thereby constructing A working network of proteins. On this basis, we need to analyze their working methods at a higher level of dynamic changes of cells, focusing on interpreting the code of vesicle transport, so as to better understand the nature of vitality. In addition, does the understanding of such a sophisticated traffic control mechanism in the cell also have useful implications for urban traffic management in our real life?

Vesicle transport participates in many important life activities of cells, such as the release of neurotransmitters and information transmission, hormone secretion, innate immunity, etc. Its transportation obstacles can cause a variety of organelle defects and cell dysfunction, and are associated with many major diseases ( Such as neurodegenerative diseases, schizophrenia, diabetes and other metabolic diseases, infections and the development of immune deficiency, tumors, etc.) are closely related. Studying the vesicle transport of cells will not only have a positive effect on the basic theoretical research of cell biology, but also reveal some major disease mechanisms that affect human health, provide new strategies or targets for their treatment, and produce human health. Important and positive impact.

The research field of "vesicle transport" has received 4 Nobel Prizes in Physiology or Medicine (in 1974, 1985, 1999, and 2013, every 10 years). The understanding of the transportation system is still preliminary and framing. The finer regulation mechanism of vesicle transport needs to be further clarified. A basic proposition that biologists face is still how to ensure the orderly, busy, and uncluttered transport of high-load materials in cells. Among them, the precise identification of the goods to be transported, the directional transportation and the unloading of the destination are the key links of vesicle transportation.

Vesicle transport has attracted the attention of scientists. It mainly began in the 1960s. George Palade and others discovered that proteins secreted by cells need to enter the endoplasmic reticulum, go to the Golgi, and then be secreted outside the cell. This great discovery of the cell's secretory pathway earned him the 1974 Nobel Prize in Physiology or Medicine. Nevertheless, the details of this secretory pathway are unclear. In 1975 Gunter Blobel further proposed the signal peptide theory of secreted proteins entering the endoplasmic reticulum, and thus won the 1999 Nobel Prize in Physiology or Medicine.

On October 7, 2013, the Nobel Prize in Physiology or Medicine was announced. The prize was awarded to three scientists who discovered the regulation mechanism of cell vesicle transport, respectively James E. Rosman, director of the Department of Cell Biology at Yale University. Rothman), Randy W. Schekman, Professor of Molecular and Cell Biology at the University of California, Berkeley, and Thomas C. Südhof, Professor of Molecular and Cell Physiology at Stanford University.