Molecules and Mysteries: Unraveling Ubiquitin for Eye Health

Main Category: Nutrition / Diet
Article Date: 16 Nov 2004 - 0:00 PDT

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Most people, scientists included, had not heard of the protein ubiquitin until a few weeks ago when the 2004 Nobel Prize in Chemistry was awarded to three scientists for their groundbreaking work on the subject. While it might not become a household word overnight, the Nobel Prize award certainly means that ubiquitin will become better understood and more prominent in scientific research.

Allen Taylor, PhD, director of the Laboratory for Nutrition and Vision Research, and his colleagues at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, have been researching the role of ubiquitin in eye health since 1982. Taylor describes ubiquitin this way, "ubiquitin, as is implied in its name, is found in every cell in the animal and plant kingdoms. It is like a molecular flag. When ubiquitin is attached to damaged or obsolete cellular proteins, it functions as 'the kiss of death' signaling that these cells with ubiquitin attached should be degraded or removed. This process occurs by what is called the ubiquitin pathway. It is essential that damaged proteins are removed, because if they are not, they accumulate and are toxic to cells-this is what happens during aging."

One contribution by Taylor and other Tufts researchers has been to show that when the ubiquitin pathway functions poorly, damaged proteins accumulate. This can lead to diseases such as cataracts and age-related macular degeneration.

Tufts researchers have also demonstrated that stresses caused by free radicals, molecules which attack ubiquitin and other proteins in the eye, wipe out the benefit-giving ubiquitin pathway. Free radicals are thought to be a fundamental cause of many degenerative diseases and the aging process and can be produced naturally in the body over time, or they can be caused by environmental factors-such as air pollution, cigarette smoking, and pesticides. Antioxidants, found in many fruits and vegetables, prevent further damage in the cell by quenching these free radicals. Taylor and his colleagues are currently examining ways in which nutrients, such as antioxidants, might be used to reduce the stresses in the eye which contribute to the diminished function of the ubiquitin pathway.

"We hope to find a way to extend the lifetime of ubiquitin, and thereby slow down or prevent the onset of eye disease," said Taylor, who is also a professor at the Friedman School of Nutrition Science and Policy at Tufts, and a professor of biochemistry and ophthalmology at Tufts School of Medicine.

Ubiquitin was discovered about 25 years ago, which is not considered to be a long time in science. Taylor notes that since that time, scientists have learned of its role in numerous cell functions. The ubiquitin pathway also plays major roles in many other cellular processes such as cell division, DNA repair, immune functions, and even gene expression, which determines what kind of cell a progenitor , or stem, cell becomes, making it a rich target for research on health, disease and aging.

November nutrition news from the Friedman School of Nutrition Science and Policy at Tufts

Contact: Siobhan Gallagher
siobhan.gallagher@tufts.edu
617-636-6586
Tufts University

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