Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Deacetylation of the retinoblastoma tumour suppressor protein by SIRT1.

ABSTRACT: The activity of Rb (retinoblastoma protein) is regulated by phosphorylation and acetylation events. Active Rb is hypophosphorylated and acetylated on multiple residues. Inactivation of Rb involves concerted hyper-phosphorylation by cyclin-CDK (cyclin-dependent kinase) complexes combined with deacetylation of appropriate lysine residues within Rb. In the present study, using in vivo co-immunoprecipitation experiments, we identified mammalian SIRT1 (sirtuin 1) as a binding partner for Rb and its family members p107 and p130. Formation of Rb-SIRT1 complexes required the pocket domain of Rb. p300 catalysed the acetylation of Rb, and SIRT1 was a potent deacetylase for Rb. The ability of SIRT1 to catalyse the deacetylation of Rb was dependent on NAD and was inhibited by the SIRT1 inhibitor nicotinamide. Deacetylated lysine residues within Rb formed a domain similar to the SIRT1-targeted domain of the p53 tumour suppressor protein. Cultures of arrested cells, via contact inhibition or DNA damage, exhibited decreased Rb phosphorylation and increased Rb acetylation. Overexpression of SIRT1 in either confluent or etoposide-treated cells resulted in a significant reduction in Rb acetylation, which was restored with nicotinamide. Gene knockdown of SIRT1 by siRNA (short interfering RNA) produced an accumulation of acetylated Rb. This increase was augmented further when siRNA against SIRT1 was used in conjunction with nicotinamide. In conclusion, our results demonstrate that SIRT1 is an in vitro and in vivo deacetylase for the Rb tumour suppressor protein.

SUBMITTER: Wong S

PROVIDER: S-EPMC2275065 | biostudies-other | 2007 Nov

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Tudor-domain protein PHF20L1 reads lysine methylated retinoblastoma tumour suppressor protein.

Project description:The retinoblastoma tumour suppressor protein (pRb) classically functions to regulate early cell cycle progression where it acts to enforce a number of checkpoints in response to cellular stress and DNA damage. Methylation at lysine (K) 810, which occurs within a critical CDK phosphorylation site and antagonises a CDK-dependent phosphorylation event at the neighbouring S807 residue, acts to hold pRb in the hypo-phosphorylated growth-suppressing state. This is mediated in part by the recruitment of the reader protein 53BP1 to di-methylated K810, which allows pRb activity to be effectively integrated with the DNA damage response. Here, we report the surprising observation that an additional methylation-dependent interaction occurs at K810, but rather than the di-methyl mark, it is selective for the mono-methyl K810 mark. Binding of the mono-methyl PHF20L1 reader to methylated pRb occurs on E2F target genes, where it acts to mediate an additional level of control by recruiting the MOF acetyltransferase complex to E2F target genes. Significantly, we find that the interplay between PHF20L1 and mono-methyl pRb is important for maintaining the integrity of a pRb-dependent G1-S-phase checkpoint. Our results highlight the distinct roles that methyl-lysine readers have in regulating the biological activity of pRb.

| S-EPMC5686351 | biostudies-literature

Proapoptotic function of the retinoblastoma tumor suppressor protein.

Project description:The retinoblastoma protein (pRB) tumor suppressor blocks cell proliferation by repressing the E2F transcription factors. This inhibition is relieved through mitogen-induced phosphorylation of pRB, triggering E2F release and activation of cell-cycle genes. E2F1 can also activate proapoptotic genes in response to genotoxic or oncogenic stress. However, pRB's role in this context has not been established. Here we show that DNA damage and E1A-induced oncogenic stress promote formation of a pRB-E2F1 complex even in proliferating cells. Moreover, pRB is bound to proapoptotic promoters that are transcriptionally active, and pRB is required for maximal apoptotic response in vitro and in vivo. Together, these data reveal a direct role for pRB in the induction of apoptosis in response to genotoxic or oncogenic stress.

| S-EPMC2880703 | biostudies-literature

Regulation of glycolytic enzyme phosphoglycerate mutase-1 by Sirt1 protein-mediated deacetylation.

Project description:Emerging proteomic evidence suggests that acetylation of metabolic enzymes is a prevalent post-translational modification. In a few recent reports, acetylation down-regulated activity of specific enzymes in fatty acid oxidation, urea cycle, electron transport, and anti-oxidant pathways. Here, we reveal that the glycolytic enzyme phosphoglycerate mutase-1 (PGAM1) is negatively regulated by Sirt1, a member of the NAD(+)-dependent protein deacetylases. Acetylated PGAM1 displays enhanced activity, although Sirt1-mediated deacetylation reduces activity. Acetylation sites mapped to the C-terminal "cap," a region previously known to affect catalytic efficiency. Overexpression of a constitutively active variant (acetylated mimic) of PGAM1 stimulated flux through glycolysis. Under glucose restriction, Sirt1 levels dramatically increased, leading to PGAM1 deacetylation and attenuated activity. Previously, Sirt1 has been implicated in the adaptation from glucose to fat burning. This study (i) demonstrates that protein acetylation can stimulate metabolic enzymes, (ii) provides biochemical evidence that glycolysis is modulated by reversible acetylation, and (iii) demonstrates that PGAM1 deacetylation and activity are directly controlled by Sirt1.

| S-EPMC3281715 | biostudies-literature

RNA polymerase III repression by the retinoblastoma tumor suppressor protein.

Project description:The retinoblastoma (RB) tumor suppressor protein regulates multiple pathways that influence cell growth, and as a key regulatory node, its function is inactivated in most cancer cells. In addition to its canonical roles in cell cycle control, RB functions as a global repressor of RNA polymerase (Pol) III transcription. Indeed, Pol III transcripts accumulate in cancer cells and their heightened levels are implicated in accelerated growth associated with RB dysfunction. Herein we review the mechanisms of RB repression for the different types of Pol III genes. For type 1 and type 2 genes, RB represses transcription through direct contacts with the core transcription machinery, notably Brf1-TFIIIB, and inhibits preinitiation complex formation and Pol III recruitment. A contrasting model for type 3 gene repression indicates that RB regulation involves stable and simultaneous promoter association by RB, the general transcription machinery including SNAPc, and Pol III, suggesting that RB may impede Pol III promoter escape or elongation. Interestingly, analysis of published genomic association data for RB and Pol III revealed added regulatory complexity for Pol III genes both during active growth and during arrested growth associated with quiescence and senescence. This article is part of a Special Issue entitled: Transcription by Odd Pols.

| S-EPMC3549324 | biostudies-literature

The coronavirus endoribonuclease Nsp15 interacts with retinoblastoma tumor suppressor protein.

Project description:Coronaviruses encode an endoribonuclease, Nsp15, which has a poorly defined role in infection. Sequence analysis revealed a retinoblastoma protein-binding motif (LXCXE/D) in the majority of the Nsp15 of the severe acute respiratory syndrome coronavirus (SARS-CoV) and its orthologs in the alpha and beta coronaviruses. The endoribonuclease activity of the SARS-CoV Nsp15 (sNsp15) was stimulated by retinoblastoma protein (pRb) in vitro, and the two proteins can be coimmunoprecipitated from cellular extracts. Mutations in the pRb-binding motif rendered sNsp15 to be differentially modified by ubiquitin in cells, and cytotoxicity was observed upon its expression. Expression of the sNsp15 in cells resulted in an increased abundance of pRb in the cytoplasm, decreased overall levels of pRb, an increased proportion of cells in the S phase of the cell cycle, and an enhanced expression from a promoter normally repressed by pRb. The endoribonuclease activity of the mouse hepatitis virus (MHV) A59 Nsp15 was also increased by pRb in vitro, and an MHV with mutations in the LXCXE/D-motif, named vLC, exhibited a smaller plaque diameter and reduced the virus titer by ∼1 log. Overexpression of pRb delayed the viral protein production by wild-type MHV but not by vLC. This study reveals that pRb and its interaction with Nsp15 can affect coronavirus infection and adds coronaviruses to a small but growing family of RNA viruses that encode a protein to interact with pRb.

| S-EPMC3318636 | biostudies-literature

Sirt1-inducible deacetylation of p21 promotes cardiomyocyte proliferation.

Project description:Inducing cardiomyocyte proliferation is a hopeful approach for cardiac regeneration following myocardial infarction. Previous studies have shown that p21 inhibits the cardiomyocyte proliferation and cardiac regeneration. Deacetylation of p21 by Sirt1 deacetylase may reduce p21 abundance and remove p21-induced cell cycle arrest. However, whether p21 deacetylation and Sirt1 deacetylate control cardiomyocyte proliferation is unclear. Here, we show that acetylation of p21 induces cardiomyocyte proliferation arrest, whereas blocking the acetylation of p21 increases cardiomyocyte proliferation. P21 can be acetylated by Sirt1, and Sirt1 activate p21 ubiquitination through deacetylation. Additionally, overexpression of Sirt1 induces EdU-, pH3-, and Aurora B-positive cardiomyocytes in neonatal and adult mice. In contrast, depletion of Sirt1 reduces cardiomyocyte proliferation in vitro and in vivo. Moreover, Sirt1 protects cardiac function, reduces cardiac remodeling, inhibits cardiomyocyte apoptosis, and attenuates cardiomyocyte hypertrophy post-myocardial infarction. These results suggest that Sirt1-induced p21 deacetylation plays an essential role in cardiomyocyte proliferation and that it could be a novel therapeutic strategy for myocardial infarction.

| S-EPMC6949046 | biostudies-literature

Retinoblastoma tumor suppressor protein in pancreatic progenitors controls ?- and ?-cell fate.

Project description:Pancreatic endocrine cells expand rapidly during embryogenesis by neogenesis and proliferation, but during adulthood, islet cells have a very slow turnover. Disruption of murine retinoblastoma tumor suppressor protein (Rb) in mature pancreatic ?-cells has a limited effect on cell proliferation. Here we show that deletion of Rb during embryogenesis in islet progenitors leads to an increase in the neurogenin 3-expressing precursor cell population, which persists in the postnatal period and is associated with increased ?-cell mass in adults. In contrast, Rb-deficient islet precursors, through repression of the cell fate factor aristaless related homeobox, result in decreased ?-cell mass. The opposing effect on survival of Rb-deficient ?- and ?-cells was a result of opposing effects on p53 in these cell types. As a consequence, loss of Rb in islet precursors led to a reduced ?- to ?-cell ratio, leading to improved glucose homeostasis and protection against diabetes.

| S-EPMC3767525 | biostudies-literature

SIRT1-mediated deacetylation of MeCP2 contributes to BDNF expression.

Project description:Methyl-CpG binding protein 2 (MeCP2) binds methylated cytosines at CpG sites on DNA and it is thought to function as a critical epigenetic regulator. Mutations in the MeCP2 gene have been associated to Rett syndrome, a human neurodevelopmental disorder. Here we show that MeCP2 is acetylated by p300 and that SIRT1 mediates its deacetylation. SIRT1, the mammalian homologue of Sir2 in yeast, is a nicotinamide-adenine dinucleotide (NAD(+))-dependent histone deacetylase that belongs to the family of HDAC class III sirtuins. Importantly, SIRT1 has been shown to play a critical role in synaptic plasticity and memory formation. This study reveals a functional interplay between two critical epigenetic regulators, MeCP2 and SIRT1, which controls MeCP2 binding activity to the brain-derived neurotrophic factor (BDNF) promoter in a specific region of the brain.

| S-EPMC3414390 | biostudies-literature

MST1 promotes apoptosis through regulating Sirt1-dependent p53 deacetylation.

Project description:Mammalian Sterile 20-like kinase 1 (MST1) protein kinase plays an important role in the apoptosis induced by a variety of stresses. The MST1 is a serine/threonine kinase that is activated upon apoptotic stimulation, which in turn activates its downstream targets, JNK/p38, histone H2B and FOXO. It has been reported that overexpression of MST1 initiates apoptosis by activating p53. However, the molecular mechanisms underlying MST1-p53 signaling during apoptosis are unclear. Here, we report that MST1 promotes genotoxic agent-induced apoptosis in a p53-dependent manner. We found that MST1 increases p53 acetylation and transactivation by inhibiting the deacetylation of Sirtuin 1 (Sirt1) and its interaction with p53 and that Sirt1 can be phosphorylated by MST1 leading to the inhibition of Sirt1 activity. Collectively, these findings define a novel regulatory mechanism involving the phosphorylation of Sirt1 by MST1 kinase which leads to p53 activation, with implications for our understanding of signaling mechanisms during DNA damage-induced apoptosis.

| S-EPMC3044949 | biostudies-literature

Lysine deacetylation in ischaemic preconditioning: the role of SIRT1.

Project description:AimsAcute ischaemic preconditioning (IPC) induces protection against cardiac ischaemia-reperfusion (IR) via post-translational modification of key proteins. Lysine (Lys) acetylation is an important regulator of protein function, but this type of modification has not been studied in the context of IPC. We investigated Lys acetylation in IPC and its upstream regulation by SIRT1.Methods and resultsHearts from C57BL/6 mice were Langendorff-perfused and subjected to IPC and IR injury. Mice were exposed to IPC by in vivo coronary artery occlusion. An isolated cardiomyocyte model of IPC was also developed. Lys acetylation was measured by western blotting, and pharmacological modulators of Lys acetylation were tested. More Lys deacetylation was observed in IPC, in the Langendorff, in vivo, and cellular IPC models; this was concurrent with an increase in SIRT1 activity measured by p53 Lys₃₇₉ deacetylation. IPC was not accompanied by changes in SIRT1 protein level, but evidence was obtained for SIRT1 modification by Small Ubiquitin-like Modifier (SUMOylation) in IPC. Furthermore, the specific SIRT1 inhibitor splitomicin reversed both IPC-mediated Lys deacetylation and IPC-induced cardioprotection. Inhibition of nicotinamide phosphoribosyltransferase (Nampt, an important enzyme which regulates SIRT1 activity by maintaining availability of the substrate NAD(+)) also blocked both IPC-induced deacetylation and cardioprotection.ConclusionLys deacetylation occurs during IPC and an elevation in SIRT1 activity plays a role in this phenomenon. Inhibition of SIRT1, either directly or by restricting the availability of its substrate NAD(+), inhibits IPC. Together these data suggest a role for SIRT1-mediated Lys deacetylation in the mechanism of acute IPC.

| S-EPMC3028968 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data