Mechanism keeps track of the time cells take to split, sounding the alarm on cells that may turn cancerous

From the press release:

University of California San Diego scientists reporting in the journal Science have found a key mechanism that keeps track of mitosis timing and takes note when the process takes too long. Researchers with the labs of Professors Arshad Desai and Karen Oegema in the School of Biological Sciences and School of Medicine have, for the first time, described the details of the mitosis “stopwatch” and the ways that suspicious cells are detected and stopped from further proliferating.

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The researchers discovered that the stopwatch is made up of a biochemical pathway that continually surveils the amount of time spent in mitosis. The pathway features a “memory” function that sums up mitosis delays from one generation to the next. Underlying the pathway is a complex of three proteins, including p53, encoded by the most commonly mutated gene in human cancers. Through a series of experiments, the researchers followed the pathway from parent to daughter and granddaughter cells over a 48-hour period. They found that the pathway works as a quality control mechanism that “remembers” mitotic time. Even cell divisions that are sequentially delayed by as little as 20 minutes are labeled as risky, they found.