Regulating transcription factor activity by phosphorylation.

The initiation of transcription by RNA polymerase II is controlled by transcription factors. Changes in gene transcription are brought about by regulating the activity of these factors. Phosphorylation of transcription factors as a regulatory mechanism is both rapid and readily reversible. Furthermore, because a transcription factor can be targeted by many protein kinases and phosphatases, phosphorylation can effectively integrate information carried by multiple signal transduction pathways, thus providing opportunities for great versatility and flexibility in gene regulation.