Protein-dependent 'switch' regulates intracellular trafficking in epithe...( NEW YORK (Dec. 10 2007) -- With find...),Health

NEW YORK (Dec. 10, 2007) -- With findings highlighted on a recent cover of Developmental Cell, researchers at Weill Cornell Medical College in New York City have shed important new light on key trafficking mechanisms within epithelial cells. Epithelial cells line the outside of nearly all organs.

Specifically, the team has discovered a molecular "switch" in developed epithelial cells that selects from a large family of "motor proteins," called kinesins. Each kinesin facilitates the transport of specific surface markers from production sites inside the cell to their ultimate home on the cell's surface.

"Not only are many more kinesins present in cells than previously thought, but their selectivity helps direct which packages of surface proteins are transported, as well as their ultimate destinations," explains lead researcher Dr. Geri Kreitzer, assistant professor in the department of cell and developmental biology at Weill Cornell Medical College.

"Breakdown in these types of intracellular trafficking pathways is a serious contributing factor to many diseases ranging from cystic fibrosis to cancer," Dr. Kreitzer continues. "So, a better understanding of processes directed by the specific kinesin family members marks a big step forward in developing therapeutics that might someday treat or cure these illnesses. By targeting the individual motors rather than the tracks along which they all move (a current approach used to treat some types of cancer), we could bypass some of the effects on global cellular function that affect patients adversely."

Scientists have long understood the importance of kinesins in the life of the cell, she notes.

"These proteins are essentially 'trains' pulling packets (vesicles) of essential proteins and lipids from production sites in the heart of the cell up to areas on the outer surface, where the cell interacts with its environment," Dr. Kreitzer explains.

These kinesin "trai
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