胆固醇,细胞膜 z-bo 2020-10-30 366

　　For more than a decade, scientists have admitted that cholesterol (an important component of cell membranes) cannot uniformly affect different types of membranes. However, a new study led by Lana Ashkar, assistant professor of physics at Virginia Tech, found that cholesterol actually conforms to biophysical principles.

　　The discovery was recently published in PNAS magazine. This research has important implications for the design of drug delivery methods and many other biological applications that require specific assumptions about the role of cholesterol in cells.

　　Ashka said: "As you know, cholesterol promotes the accumulation of molecules in cell membranes. In this study, we proved that cholesterol causes membranes to harden at the nanoscale according to the laws of physics. These findings help us understand cholesterol biology. Impact. Understand their role in function, health and disease."

　　The cell membrane is a thin layer of fat molecules that can define cell boundaries and is a variety of organisms including virus transmission and cell division. It has a regulating function. To achieve this function, the membrane structure must be able to bend to change its shape. This tendency to bend depends on the degree of packing of molecular structural units. Ashkar added that when the packaging is tight, the film will become hard and not bend easily.

　　Bacon, eggs, cheese and many other comfort foods contain a lot of cholesterol. Excessive cholesterol can damage the human body, but the normal function of cells absolutely needs to regulate cell membrane cholesterol. Abnormal cholesterol levels are usually associated with a variety of medical conditions.

　　Except for cholesterol, our cell membranes are mainly composed of lipids. Lipids are small molecules of fat. When present in water, they will automatically assemble into a double-layer structure. About 60% of the human body is composed of water. Lipids and cholesterol together form a barrier that restricts our cells and regulates their nutrient exchange.

　　At the molecular level, cholesterol has a smooth and rigid structure. When it interacts with our cell membranes, they block between lipids, resulting in higher membrane density. According to the relationship between structure and properties, the film can be cured naturally. In the past ten years, physicists and biologists have believed that cholesterol has little effect on the stiffness of membranes formed by cis-unsaturated lipids. Ashka said: "This goes against our understanding of the role of cholesterol in cell membranes." "This also contradicts the relationship between the standard structure and the properties of self-assembled materials."

　　Ideally, the cell membrane should maintain a semi-rigid structure. It is hard enough to maintain its shape, but flexible enough to make the signaling protein and functional domain effective. Dynamic movement. Misunderstandings about how cholesterol strengthens cell membranes affect our understanding of membrane function.

　　The initial data didn't make much sense, but during careful inspection, Ashkar found an obvious case. According to the parameters of the observation method, the soft material showed "significantly" different characteristics. .. She discovered that a major signal transduction event occurred within a short period of time, and the added cholesterol hardened the membrane.