ARTD1 regulates cyclin E expression and consequently cell-cycle re-entry and G1/S progression in T24 bladder carcinoma cells.

ADP-ribosylation is involved in a variety of biological processes, many of which are chromatin-dependent and linked to important functions during the cell cycle. However, any study on ADP-ribosylation and the cell cycle faces the problem that synchronization with chemical agents or by serum starvation and subsequent growth factor addition already activates ADP-ribosylation by itself. Here, we investigated the functional contribution of ARTD1 in cell cycle re-entry and G1/S cell cycle progression using T24 urinary bladder carcinoma cells, which synchronously re-enter the cell cycle after splitting without any additional stimuli.

WNT/β-catenin signaling inhibits CBP-mediated RelA acetylation and expression of proinflammatory NF-κB target genes.

The discovery of functional crosstalk between WNT and nuclear factor κB (NF-κB) signaling has established a more complex role for these two pathways in inflammation and cancer. However, the molecular mechanisms of the crosstalk and its biological consequences are largely unknown. Here, we show that WNT/β-catenin signaling selectively inhibits the expression of a proinflammatory subset of IL-1β-induced NF-κB target genes.

SET7/9-dependent methylation of ARTD1 at K508 stimulates poly-ADP-ribose formation after oxidative stress.

ADP-ribosyltransferase diphtheria toxin-like 1 (ARTD1, formerly PARP1) is localized in the nucleus, where it ADP-ribosylates specific target proteins. The post-translational modification (PTM) with a single ADP-ribose unit or with polymeric ADP-ribose (PAR) chains regulates protein function as well as protein-protein interactions and is implicated in many biological processes and diseases. SET7/9 (Setd7, KMT7) is a protein methyltransferase that catalyses lysine monomethylation of histones, but also methylates many non-histone target proteins such as p53 or DNMT1.

Crosstalk between SET7/9-dependent methylation and ARTD1-mediated ADP-ribosylation of histone H1.4.

Background: Different histone post-translational modifications (PTMs) fine-tune and integrate different cellular signaling pathways at the chromatin level. ADP-ribose modification of histones by cellular ADP-ribosyltransferases such as ARTD1 (PARP1) is one of the many elements of the histone code. All 5 histone proteins were described to be ADP-ribosylated in vitro and in vivo.

Acetylation of p65 at lysine 314 is important for late NF-kappaB-dependent gene expression.

Background: NF-kappaB regulates the expression of a large number of target genes involved in the immune and inflammatory response, apoptosis, cell proliferation, differentiation and survival. We have earlier reported that p65, a subunit of NF-kappaB, is acetylated in vitro and in vivo at three different lysines (K310, K314 and K315) by the histone acetyltransferase p300.

Results: In this study, we describe that site-specific mutation of p65 at lysines 314 and 315 enhances gene expression of a subset of NF-kappaB target genes including Mmp10 and Mmp13.

Molecular mechanism of poly(ADP-ribosyl)ation by PARP1 and identification of lysine residues as ADP-ribose acceptor sites.

Poly(ADP-ribose) polymerase 1 (PARP1) synthesizes poly(ADP-ribose) (PAR) using nicotinamide adenine dinucleotide (NAD) as a substrate. Despite intensive research on the cellular functions of PARP1, the molecular mechanism of PAR formation has not been comprehensively understood. In this study, we elucidate the molecular mechanisms of poly(ADP-ribosyl)ation and identify PAR acceptor sites.

p300-mediated acetylation of the Rothmund-Thomson-syndrome gene product RECQL4 regulates its subcellular localization.

RECQL4 belongs to the conserved RecQ family of DNA helicases, members of which play important roles in the maintenance of genome stability in all organisms that have been examined. Although genetic alterations in the RECQL4 gene are reported to be associated with three autosomal recessive disorders (Rothmund-Thomson, RAPADILINO and Baller-Gerold syndromes), the molecular role of RECQL4 still remains poorly understood. Here, we show that RECQL4 specifically interacts with the histone acetyltransferase p300 (also known as p300 HAT), both in vivo and in vitro, and that p300 acetylates one or more of the lysine residues at positions 376, 380, 382, 385 and 386 of RECQL4.

Importin alpha binding and nuclear localization of PARP-2 is dependent on lysine 36, which is located within a predicted classical NLS.

Background: The enzymes responsible for the synthesis of poly-ADP-ribose are named poly-ADP-ribose polymerases (PARP). PARP-2 is a nuclear protein, which regulates a variety of cellular functions that are mainly controlled by protein-protein interactions. A previously described non-conventional bipartite nuclear localization sequence (NLS) lies in the amino-terminal DNA binding domain of PARP-2 between amino acids 1-69; however, this targeting sequence has not been experimentally examined or validated.

Identification of lysines 36 and 37 of PARP-2 as targets for acetylation and auto-ADP-ribosylation.

Poly-ADP-ribose polymerase-2 (PARP-2) was described to regulate cellular functions comprising DNA surveillance, inflammation and cell differentiation by co-regulating different transcription factors. Using an in vitro and in vivo approach, we identified PARP-2 as a new substrate for the histone acetyltransferases PCAF and GCN5L. Site directed mutagenesis indicated that lysines 36 and 37, located in the nuclear localization signal of PARP-2, are the main targets for PCAF and GCN5L activity in vitro.

Functional relevance of novel p300-mediated lysine 314 and 315 acetylation of RelA/p65.

Nuclear factor kappaB (NF-kappaB) plays an important role in the transcriptional regulation of genes involved in immunity and cell survival. We show here in vitro and in vivo acetylation of RelA/p65 by p300 on lysine 314 and 315, two novel acetylation sites. Additionally, we confirmed the acetylation on lysine 310 shown previously.