The COOH-terminal region of pRb2/p130 binds to histone deacetylase 1 (HDAC1), enhancing transcriptional repression of the E2F-dependent cyclin A promoter.

The tumor suppressor retinoblastoma protein family members pRb, p107, and pRb2/p130 are potent negative transcriptional regulators. The best understood target is the transcription factor E2F, which activates cell cycle-dependent transcription of genes controlling and promoting the cell division cycle (e.g., cyclin A). pRb2/p130 is known to be important in implementing cell cycle exit into G0 due to serum deprivation or various differentiation programs. Several recent studies demonstrated the effect histone acetylases and histone deacetylases (HDACs) have on fine-tuning transcriptional regulation of eucaryotic cells. In this study, we demonstrate that pRb2/p130 binds to HDAC1. This interaction increases the ability of pRb2/p130 to inhibit transcription of the E2F-dependent cyclin A promoter in vivo. We also identify the COOH-terminal 35aa as being necessary for stable interaction between HDAC1 and pRb2/p130.