Fat Found to Have a Healthy Role in the Body

Scientists have found that tiny balls of fat existing in most cells of the body play an important role in regulating excess proteins in the body.

In a study of fruit flies, Steven Gross, associate professor of developmental and cell biology at the University of California, Irvine (UC Irvine, USA), and colleagues found that these fat droplets served as storage depots for a type of protein used mainly by a cell to bind DNA and organize it in the nucleus. The fat keeps this protein out of the way until it is needed, so that it cannot cause harm within the cell. These findings imply that the fat droplets could also serve as storage warehouses for other excess proteins that otherwise might cause harm if not sequestered. These findings were reported in the September 19, 2006, issue of Current-Biology.

The researchers used fruit flies in their experiments because of the strong similarities between the fat droplets in the flies and those in mammals. After purifying the droplets in fruit fly embryos, they used mass spectrometry to look at which proteins, if any, were associated with the droplets. They were surprised to find histones, a protein used by the cell to fold DNA within the nucleus. Although these serve no purpose outside the nucleus, the researchers found that 50% of all histones present in the cell were in the fat droplets. The amount of histones in the droplets diminished as the embryo moved from early development to later stages. In essence, the fat droplets served as a warehouse where the proteins could be stored until needed by the cell's nucleus.

"We are surprised to find that these droplets appear to be a mechanism for cleaning up excess proteins before they cause trouble,” said Prof. Gross. "Obviously, everything in the body should be balanced. There is no doubt that huge amounts of fat tax your system in a lot of ways. But there now appears to be growing evidence that fat is also important for keeping us healthy.”

Prof. Gross and his colleagues believe the droplets serve the same purpose in other excess proteins as well, which has implications for the way fat may be helping to fight certain diseases when too much of certain proteins are produced.

"In prion diseases, such as Mad Cow disease, for example, proteins in the brain are misshapen,” said Prof. Gross. "They become abnormal, clump together, and accumulate on brain tissue. Although we have no evidence yet that fat droplets could help with this, prion diseases are one area in which we can explore further to see if these droplets are helping keep excess bothersome proteins out of the way.”



Related Links:
University of California, Irvine