BOSTON – Cataract is one of the most common eye diseases, becoming more prevalent as people age. Over half of adults in the United States develop cataracts before age 80 and more than six million have undergone surgery to prevent vision loss caused by the clouding of the eye lens.*
Now, a team of scientists has established that a breakdown in communication between two biochemical pathways in the eye is involved in causing cataracts. The new information could help researchers develop pharmaceutical and dietary approaches to delaying the onset of cataracts. Scientists from the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University led the study in mice and their results are published in the January 12-16 Online Early Edition of the Proceedings of the National Academy of Sciences.
Cataracts are caused in part by the accumulation of abnormal proteins. Normally, obsolete or damaged proteins are removed by the ubiquitin and lysosomal pathways. The authors noticed when the ubiquitin pathway falters calcium flows into the cells of the lens, causing a third pathway to activate. It is this third pathway that causes cataract-related damage in the eye.  
“We discovered that the ubiquitin pathway and the calpain pathway communicate with one another. When their conversation goes awry, cells start a vicious cycle in which proteins are improperly degraded,” said senior and corresponding author Allen Taylor, Ph.D., the director of Laboratory for Nutrition and Vision at the USDA HNRCA and a professor at the Friedman School of Nutrition Science and Policy at Tufts University. “This leads to alterations in proteins and the beginning of the clouding of the lens that signals the onset of cataract.”……….
Source: Health Canal