For years, researchers have puzzled over how some cells guide themselves toward a chemical that spreads itself around. Now, in this week's issue of Science, Johns Hopkins researchers identify a protein that accumulates toward the front end of a cell and helps cells "sense" their way to a target.
"Gradient sensing is important in everything from inflammation, disease fighting and blood vessel growth to wound healing and prenatal development," says Peter Devreotes, Ph.D., a professor of biochemistry and senior author of the study. The finding, he says, brings researchers one step closer to understanding this chemical-sensing mechanism and using it to develop treatments.
"If we understand the process of chemotaxis, in the future we may be able to encourage or inhibit it," says Devreotes. "This could be beneficial in encouraging wounds to heal, treating cancers by slowing blood vessel growth, or reducing inflammation thereby controlling arthritis."
The process by which cells are able to move themselves toward certain targets is known as chemotaxis. When a cell wants to attract another cell, it releases signaling molecules called chemoattractants. These molecules travel toward the other cell and set up a shallow pool around it. The cell will then move toward the source, even when the number of chemoattractant molecules near the front of the receptive cell is only 10 percent higher than near the back. In addition, one edge of the cell, known as the "leading" edge, is more sensitive to stimulation, which further helps guide the cell toward its target. Given these pieces of information, pondered researchers, how did the cell know which direction to travel and how did it determine its leading edge?
To answer the questions, Devreotes and his colleagues have been studying an amoeba named Dictyostelium, which behaves like many chemotactic cells. This "social amoeba" responds to a chemoattractant known as cAMP, and its response allows it
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Contact: Kate O'Rourke
korourke@jhmi.edu
410-955-8665
Johns Hopkins Medical Institutions
10-Feb-2000