The RB1 gene product is a tumor suppressor protein that appears to be involved in cell cycle regulation, as it is phosphorylated in the S to M phase transition and is dephosphorylated in the G1 phase of the cell cycle.

In addition, both proteins can inhibit the transcription of cell cycle genes containing E2F binding sites in their promoters.

Due to the sequence and biochemical similarities with the RB1 protein, it is thought that the protein encoded by this gene may also be a tumor suppressor.

Two transcript variants encoding different isoforms have been found for this gene.

[5] Retinoblastoma-like protein 1 has been shown to interact with: This article incorporates text from the United States National Library of Medicine, which is in the public domain.