Nutrition-minded cell cycle.

For decades, the fission yeast Schizosaccharomyces pombe has been used as an excellent model with which to explore how cellular growth is coordinated with the division cycle, a yet-unanswered question in biology. New studies in this organism show that TOR (target of rapamycin) kinase and stress-responsive MAPK (mitogen-activated protein kinase) form a signaling pathway that readjusts the timing of mitotic onset in response to poor nutrient conditions. Nutritional environment appears to be translated into graded activity of the protein kinases that influence the activation of Cdc2, a cyclin-dependent kinase driving cell-cycle progression.