Acetylation control of the retinoblastoma tumour-suppressor protein

HM Chan, M Krstic-Demonacos, L Smith… - Nature cell …, 2001 - nature.com
HM Chan, M Krstic-Demonacos, L Smith, C Demonacos, NBL Thangue
Nature cell biology, 2001nature.com
The retinoblastoma tumour-suppressor protein (pRb) and p300/CBP co-activator proteins
are important for control of proliferation and in tumour cells these are sequestered by viral
oncoproteins such as E1A. pRb is involved in negatively regulating growth, and p300/CBP
proteins have histone acetyltransferase (HAT) activity, which influences gene expression.
Although it is known that phosphorylation by G1 cyclin-dependent kinases (CDKs) regulates
pRb activity, the nature and role of other post-translational modifications is not understood …
Abstract
The retinoblastoma tumour-suppressor protein (pRb) and p300/CBP co-activator proteins are important for control of proliferation and in tumour cells these are sequestered by viral oncoproteins such as E1A. pRb is involved in negatively regulating growth, and p300/CBP proteins have histone acetyltransferase (HAT) activity, which influences gene expression. Although it is known that phosphorylation by G1 cyclin-dependent kinases (CDKs) regulates pRb activity, the nature and role of other post-translational modifications is not understood. Here we identify acetylation as a new type of modification and level of control in pRb function. Adenovirus E1A, which binds p300/CBP through an amino-terminal transformation-sensitive domain, stimulates the acetylation of pRb by recruiting p300 and pRb into a multimeric-protein complex. Furthermore, pRb acetylation is under cell-cycle control, and acetylation hinders the phosphorylation of pRb by cyclin-dependent kinases. pRb binds more strongly when acetylated to the MDM2 oncoprotein, which indicates that acetylation may regulate protein–protein interactions in the pRb pathway. The acetylation of pRb defines a new level of cell-cycle control mediated by HAT. Furthermore, our results establish a relationship between p300, pRb and acetylation in which E1A acts to recruit and target a cellular HAT activity to pRb.
nature.com