The retinoblastoma protein and its relatives.

The retinoblastoma tumor suppressor gene is inactivated in retinoblastomas and a variety of other tumor types. In addition, it is one of several cellular proteins targeted by the transforming proteins of the small DNA tumor viruses. At least two other cellular proteins that are targeted by the viral transforming proteins are structurally and functionally related to the protein encoded by the retinoblastoma tumor suppressor gene. Recent data has described a complex series of interactions with cyclins, kinases and transcription factors. It is presumably through these interactions that the retinoblastoma-related proteins exert their effects on cellular proliferation.