A protein called kinesin has an unusual property: it walks within cells, along structures called microtubules, carrying material from the center of the cell to the edges. This means that the kinesin protein plays an important role in cell division, and therefore in growth and healing. Kinesin is also part of the process by which the areas of the brain communicate with each other and with the nerves and muscles in the body.
Now researchers have found another important function kinesin performs in the body. Kinesin is involved in regulating cholesterol levels, especially the amount of "bad" LDL cholesterol. The protein plays a key role in the mechanism by which pockets in the liver draw cholesterol out of the blood, engulfing it, a process called endocytosis. The walking protein does not walk in this role; instead, it simply provides structural support to the liver cells.
The form of cholesterol this process operates on, referred to as low-density lipoprotein (LDL) cholesterol, is termed "bad" in contrast to its high-density counterpart. Excessive LDL is associated with cardiovascular disease. It causes wax-like plaque to build up within the arteries, making them narrower and more rigid. When this happens, less blood can go through the blood vessel and blood pressure increases. By contrast, HDL—which even in healthy people is less than half as common as LDL—helps clean out this plaque. That means that while it’s dangerous to have high levels of LDL, it’s also dangerous for HDL levels to be too low.
Except when it goes wrong. Recent studies have given scientists insight into how HDL can turn on people, promoting rather than preventing disease. In patients who already have clogged arteries, HDL can become dysfunctional, losing its ability to clean the arteries and raising the risk of heart disease. That’s why it’s important to pay attention to reducing bad cholesterol. That doesn’t mean avoiding foods high in cholesterol, but it does mean avoiding foods high in saturated fat, which is what raises cholesterol levels. The polyunsaturated fats in foods such as walnuts an almonds actually help to reduce LDL levels, and omega-3 fatty acids found in fish oil can likewise be beneficial. High-fiber foods, too, such as oatmeal, can help get bad cholesterol down.