CELL-CYCLE REGULATION BY THE RETINOBLASTOMA FAMILY OF GROWTH-INHIBITORY PROTEINS

The retinoblastoma family of growth-inhibitory proteins act by binding and inhibiting several proteins with growth-stimulatory activity, the most prominent of which is the cellular transcription factor E2F. In higher organisms, progression through the cell division cycle is accom panied by the cyclical activation of a number of protein kinases, the cyclin-dependent kinases. Phosphorylation of retinoblastoma family pro teins by these cyclin-dependent kinases leads to release of the associ ated growth-stimulatory proteins which in turn mediate progression thr ough the cell division cycle.