Much of cells' internal communication revolves around two very important words -- "stop" and "go" -- elicited when a small bit, called phosphate, is added onto proteins. This addition turns protein activities up or down and fine tunes cells' responses to what's happening outside their borders. This communication can go awry in diseases, including cancer, and be corrected by various drugs.
The source of these phosphate bits has been known -- a molecule called adenosine triphosphate, or ATP. But in their new report, the Johns Hopkins scientists describe a brand new source of phosphate that seems to work with as many proteins as targeted by ATP, but in a completely different way.
"There are already drugs that affect particular roles of ATP to treat cancer and other conditions, so we envision drugs that increase or decrease specific activities of this new source of phosphate could be important in neurologic and psychiatric illnesses, and perhaps in cancer as well," says Solomon Snyder, M.D., professor and director of neuroscience, one of the departments in Johns Hopkins' Institute for Basic Biomedical Sciences.
"Nobody in a million years would have thought there was another way for cells to add phosphate groups to proteins other than using ATP," he adds. "Addition of phosphates to proteins -- phosphorylation -- is the most fundamental signaling mechanism in all life, and the new source of phosphate represents a very different kind of process than the one we've known about. It represents a totally new form of cellular communication."