A positive-feedback system ensures that cells divide

(PhysOrg.com) -- In the life of every cell, there’s a point of no return. Once it enters the cell cycle and passes a checkpoint known as “Start,” a cell will follow the steps it needs to divide — no matter what changes might occur in its environment. Now, in research appearing in the July 17 issue of Nature, scientists at Rockefeller University show that a positive-feedback system ensures that a cell that has made the decision to divide finishes what it has started.