Extracellular stimuli transmit information to cells by activating receptor-dependent signal-transduction cascades, most typically involving tyrosine and serine/threonine kinases. The cell's response to the activation of these kinases depends on the duration of their signals. New work now shows how cells sense the duration of an ERK signal in the G1 phase of the cell cycle. The study suggests that a common mechanism for sensing ERK signal duration may be involved in diverse cellular functions.
