scholarly journals Lysine acetyltransferase Tip60 acetylates the APP adaptor Fe65 to increase its transcriptional activity

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Sabine Probst ◽  
Florian Riese ◽  
Larissa Kägi ◽  
Maik Krüger ◽  
Natalie Russi ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Target Genes ◽  
Adaptor Protein ◽  
Proteolytic Processing ◽  
Class Iii ◽  
Lysine Deacetylase ◽  
Lysine Residues ◽  
Lysine Acetyltransferase ◽  
Complex Forms ◽  
Spot Formation

AbstractProteolytic processing of the amyloid precursor protein (APP) releases the APP intracellular domain (AICD) from the membrane. Bound to the APP adaptor protein Fe65 and the lysine acetyltransferase (KAT) Tip60, AICD translocates to the nucleus. Here, the complex forms spherical condensates at sites of endogenous target genes, termed AFT spots (AICD-Fe65-Tip60). We show that loss of Tip60 KAT activity prevents autoacetylation, reduces binding of Fe65 and abolishes Fe65-mediated stabilization of Tip60. Autoacetylation is a prerequisite for AFT spot formation, with KAT-deficient Tip60 retained together with Fe65 in speckles. We identify lysine residues 204 and 701 of Fe65 as acetylation targets of Tip60. We do not detect acetylation of AICD. Mutation of Fe65 K204 and K701 to glutamine, mimicking acetylation-induced charge neutralization, increases the transcriptional activity of Fe65 whereas Tip60 inhibition reduces it. The lysine deacetylase (KDAC) class III Sirt1 deacetylates Fe65 and pharmacological modulation of Sirt1 activity regulates Fe65 transcriptional activity. A second acetylation/deacetylation cycle, conducted by CBP and class I/II KDACs at different lysine residues, regulates stability of Fe65. This is the first report describing a role for acetylation in the regulation of Fe65 transcriptional activity, with Tip60 being the only KAT tested that supports AFT spot formation.

scholarly journals Self-Association of Gata1 Enhances Transcriptional Activity In Vivo in Zebra Fish Embryos

2003 ◽  
Vol 23 (22) ◽  
pp. 8295-8305 ◽  
Author(s):  
Keizo Nishikawa ◽  
Makoto Kobayashi ◽  
Atsuko Masumi ◽  
Susan E. Lyons ◽  
Brant M. Weinstein ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Germ Line ◽  
Zebra Fish ◽  
Wild Type ◽  
Lysine Residues ◽  
Self Association ◽  
Gata Motif

ABSTRACT Gata1 is a prototype transcription factor that regulates hematopoiesis, yet the molecular mechanisms by which Gata1 transactivates its target genes in vivo remain unclear. We previously showed, in transgenic zebra fish, that Gata1 autoregulates its own expression. In this study, we characterized the molecular mechanisms for this autoregulation by using mutations in the Gata1 protein which impair autoregulation. Of the tested mutations, replacement of six lysine residues with alanine (Gata1KA6), which inhibited self-association activity of Gata1, reduced the Gata1-dependent induction of reporter gene expression driven by the zebra fish gata1 hematopoietic regulatory domain (gata1 HRD). Furthermore, overexpression of wild-type Gata1 but not Gata1KA6 rescued the expression of Gata1 downstream genes in vlad tepes, a germ line gata1 mutant fish. Interestingly, both GATA sites in the double GATA motif in gata1 HRD were critical for the promoter activity and for binding of the self-associated Gata1 complex, whereas only the 3′-GATA site was required for Gata1 monomer binding. These results thus provide the first in vivo evidence that the ability of Gata1 to self-associate critically contributes to the autoregulation of the gata1 gene.

scholarly journals Identification of lysine residues critical for the transcriptional activity and polyubiquitination of the NF-κB family member RelB

2008 ◽  
Vol 416 (1) ◽  
pp. 117-127 ◽  
Author(s):  
Julia Leidner ◽  
Lysann Palkowitsch ◽  
Uta Marienfeld ◽  
Dietmar Fischer ◽  
Ralf Marienfeld
Keyword(s):  
Dna Methyltransferase ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Nuclear Factor Κb ◽  
Death Domain ◽  
293 Cells ◽  
Lysine Residues ◽  
Negative Effect ◽  
The Stability

RelB is the key component of the alternative NF-κB (nuclear factor κB) signalling pathway. However, RelB exerts also a negative effect via the recruitment of a DNMT1 (DNA methyltransferase 1)–Daxx (death domain-associated protein) complex to NF-κB target genes. Importantly, the molecular mechanisms which determine the functions of RelB are still largely unknown. In the present study, we aimed to analyse whether ubiquitination of RelB might be involved in the regulation of RelB. Indeed, RelB is constitutively polyubiquitinated in the B-cell lines Namalwa and 70Z/3. Although a PMA+ionomycin-induced augmentation of RelB polyubiquitination was linked to its proteasomal degradation in B-cells, the constitutive RelB polyubiquitination seems to affect non-proteasomal functions. Consistently, a significant RelB polyubiquitination in HEK (human embryonic kidney)-293 cells correlated with an augmentation of the transcriptional activity of RelB. Yet, neither nuclear localization nor DNA binding was enhanced by RelB polyubiquitination. Interestingly, basal RelB polyubiquitination depends neither on Lys48 nor on Lys63 conjugates, but might involve unconventional ubiquitin conjugates. Mapping of the ubiquitination target sites in RelB revealed the existence of various lysine residues, which serve as ubiquitination acceptors. However, only the substitution of Lys273/274 and Lys305/308 significantly decreased the basal RelB activity and the ubiquitin-induced augmentation of the RelB activity. Collectively, these results imply a dual role of RelB polyubiquitination for the stability and activity of this transcription factor.

scholarly journals SUMO modification regulates the transcriptional activity of XBP1

2010 ◽  
Vol 429 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Hui Chen ◽  
Ling Qi
Keyword(s):  
Transcriptional Activity ◽  
Target Genes ◽  
Protein Accumulation ◽  
Transactivation Domain ◽  
Signal Transducer ◽  
Defence Mechanism ◽  
Unfolded Protein ◽  
Lysine Residues ◽  
Protein Response ◽  
Cellular Defence

The UPR (unfolded protein response), a cellular defence mechanism against misfolded protein accumulation in the ER (endoplasmic reticulum), is associated with many human diseases such as aging, cancer and diabetes. XBP1 (X-box-binding protein 1), a key transcription factor of the UPR, is critical in maintaining ER homoeostasis. Nevertheless, the mechanism by which XBP1 transcriptional activity is regulated remains unexplored. In the present study we show that XBP1s, the active spliced form of XBP1 protein, is SUMOylated, mainly by PIAS2 [protein inhibitor of activated STAT (signal transducer and activator of transcription) 2] at two lysine residues located in the C-terminal transactivation domain. Ablation of these SUMOylation events significantly enhances the transcriptional activity of XBP1s towards UPR target genes. Thus our results reveal an unexpected role for SUMO (small ubiquitin-related modifier) in the regulation of UPR activation and ER homoeostasis.

scholarly journals KAT7 is a therapeutic vulnerability of MLL-rearranged acute myeloid leukemia

2020 ◽  
Author(s):  
Yan Zi Au ◽  
Muxin Gu ◽  
Etienne De Braekeleer ◽  
Jason Yu ◽  
Swee Hoe Ong ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Developmental Disorders ◽  
Target Genes ◽  
Adaptor Proteins ◽  
Gene Promoters ◽  
Genome Wide ◽  
Lysine Residues ◽  
Acetyl Group ◽  
Lysine Acetyltransferase ◽  
Acute Myeloid

AbstractHistone acetyltransferases (HATs) catalyze the transfer of an acetyl group from acetyl-CoA to lysine residues of histones and play a central role in transcriptional regulation in diverse biological processes. Dysregulation of HAT activity can lead to human diseases including developmental disorders and cancer. Through genome-wide CRISPR-Cas9 screens, we identified several HATs of the MYST family as fitness genes for acute myeloid leukaemia (AML). Here we investigate the essentiality of lysine acetyltransferase KAT7 in AMLs driven by the MLL-X gene fusions. We found that KAT7 loss leads to a rapid and complete loss of both H3K14ac and H4K12ac marks, in association with reduced proliferation, increased apoptosis and differentiation of AML cells. Acetyltransferase activity of KAT7 is essential for the proliferation of these cells. Mechanistically, our data propose that acetylated histones provide a platform for the recruitment of MLL-fusion-associated adaptor proteins such as BRD4 and AF4 to gene promoters. Upon KAT7 loss, these factors together with RNA polymerase II rapidly dissociate from several MLL-fusion target genes that are essential for AML cell proliferation, including MEIS1, PBX3 and SENP6. Our findings reveal that KAT7 is a plausible therapeutic target for this poor prognosis AML subtype.

Review of Progress in Predicting Protein Methylation Sites

2019 ◽  
Vol 23 (15) ◽  
pp. 1663-1670 ◽  
Author(s):  
Chunyan Ao ◽  
Shunshan Jin ◽  
Yuan Lin ◽  
Quan Zou
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Transcriptional Activity ◽  
Regulation Of Gene Expression ◽  
Protein Methylation ◽  
Biological Processes ◽  
Post Translational Modification ◽  
Regulatory Enzymes ◽  
Lysine Residues ◽  
Arginine Residues

Protein methylation is an important and reversible post-translational modification that regulates many biological processes in cells. It occurs mainly on lysine and arginine residues and involves many important biological processes, including transcriptional activity, signal transduction, and the regulation of gene expression. Protein methylation and its regulatory enzymes are related to a variety of human diseases, so improved identification of methylation sites is useful for designing drugs for a variety of related diseases. In this review, we systematically summarize and analyze the tools used for the prediction of protein methylation sites on arginine and lysine residues over the last decade.

scholarly journals Deacetylation as a receptor-regulated direct activation switch for pannexin channels

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yu-Hsin Chiu ◽  
Christopher B. Medina ◽  
Catherine A. Doyle ◽  
Ming Zhou ◽  
Adishesh K. Narahari ◽  
...  
Keyword(s):  
G Protein Coupled Receptors ◽  
Activation Mechanism ◽  
Lysine Acetylation ◽  
Intercellular Signaling ◽  
Histone Deacetylase 6 ◽  
Pannexin 1 ◽  
Lysine Deacetylase ◽  
Channel Opening ◽  
Lysine Residues ◽  
G Protein Coupled

AbstractActivation of Pannexin 1 (PANX1) ion channels causes release of intercellular signaling molecules in a variety of (patho)physiological contexts. PANX1 can be activated by G protein-coupled receptors (GPCRs), including α1-adrenergic receptors (α1-ARs), but how receptor engagement leads to channel opening remains unclear. Here, we show that GPCR-mediated PANX1 activation can occur via channel deacetylation. We find that α1-AR-mediated activation of PANX1 channels requires Gαq but is independent of phospholipase C or intracellular calcium. Instead, α1-AR-mediated PANX1 activation involves RhoA, mammalian diaphanous (mDia)-related formin, and a cytosolic lysine deacetylase activated by mDia – histone deacetylase 6. HDAC6 associates with PANX1 and activates PANX1 channels, even in excised membrane patches, suggesting direct deacetylation of PANX1. Substitution of basally-acetylated intracellular lysine residues identified on PANX1 by mass spectrometry either prevents HDAC6-mediated activation (K140/409Q) or renders the channels constitutively active (K140R). These data define a non-canonical RhoA-mDia-HDAC6 signaling pathway for GαqPCR activation of PANX1 channels and uncover lysine acetylation-deacetylation as an ion channel silencing-activation mechanism.

scholarly journals Emerging multifaceted roles of BAP1 complexes in biological processes

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Aileen Patricia Szczepanski ◽  
Lu Wang
Keyword(s):  
Transcriptional Repression ◽  
Target Genes ◽  
Regulatory Mechanisms ◽  
Biological Processes ◽  
Multiprotein Complex ◽  
Downstream Target ◽  
Evolutionarily Conserved ◽  
Complex Forms ◽  
Polycomb Repressive Complex 1

AbstractHistone H2AK119 mono-ubiquitination (H2AK119Ub) is a relatively abundant histone modification, mainly catalyzed by the Polycomb Repressive Complex 1 (PRC1) to regulate Polycomb-mediated transcriptional repression of downstream target genes. Consequently, H2AK119Ub can also be dynamically reversed by the BAP1 complex, an evolutionarily conserved multiprotein complex that functions as a general transcriptional activator. In previous studies, it has been reported that the BAP1 complex consists of important biological roles in development, metabolism, and cancer. However, identifying the BAP1 complex’s regulatory mechanisms remains to be elucidated due to its various complex forms and its ability to target non-histone substrates. In this review, we will summarize recent findings that have contributed to the diverse functional role of the BAP1 complex and further discuss the potential in targeting BAP1 for therapeutic use.

scholarly journals Gene expression profiling of gastrin target genes in parietal cells

2006 ◽  
Vol 24 (2) ◽  
pp. 124-132 ◽  
Author(s):  
Renu N. Jain ◽  
Cynthia S. Brunkan ◽  
Catherine S. Chew ◽  
Linda C. Samuelson
Keyword(s):  
Gene Expression ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Parietal Cell ◽  
Target Genes ◽  
Adaptor Protein ◽  
Parietal Cells ◽  
Cell Gene Expression ◽  
Cell Gene

Previous studies demonstrated that mice with a null mutation in the gene encoding the hormone gastrin have impaired gastric acid secretion. Hence, the aim of this study was to evaluate changes in the acid-secreting parietal cell in gastrin-deficient (GAS-KO) mice. Analysis of several transcripts encoding parietal cell proteins involved in gastric acid secretion showed reduced abundance in the GAS-KO stomach, including H+,K+-ATPase α- and β-subunits, KCNQ1 potassium channel, aquaporin-4 water channel, and creatine kinase B, which were reversed by gastrin infusion for 1 wk. Although mRNA and protein levels of LIM and SH3 domain-containing protein-1 (LASP-1) were not greatly changed in the mutant, there was a marked reduction in phosphorylation, consistent with its proposed role as a cAMP signal adaptor protein associated with acid secretion. A more comprehensive analysis of parietal cell gene expression in GAS-KO mice was performed using the Affymetrix U74AV2 chip with RNA from parietal cells purified by flow cytometry to >90%. Comparison of gene expression in GAS-KO and wild-type mice identified 47 transcripts that differed by greater than or equal to twofold, suggesting that gastrin affects parietal cell gene expression in a specific manner. The differentially expressed genes included several genes in signaling pathways, with a substantial number (20%) known to be target genes for Wnt and Myc.

scholarly journals Differential Regulation of Estrogen-Inducible Proteolysis and Transcription by the Estrogen Receptor α N Terminus

2005 ◽  
Vol 25 (13) ◽  
pp. 5417-5428 ◽  
Author(s):  
Christopher C. Valley ◽  
Raphaël Métivier ◽  
Natalia M. Solodin ◽  
Amy M. Fowler ◽  
Mara T. Mashek ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Estrogen Receptor Α ◽  
Transactivation Domain ◽  
Related Factors ◽  
Additional Element ◽  
Transactivation Domains ◽  
Ubiquitin Proteasome ◽  
Transcriptional Complex

ABSTRACT The ubiquitin-proteasome pathway has emerged as an important regulatory mechanism governing the activity of several transcription factors. While estrogen receptor α (ERα) is also subjected to rapid ubiquitin-proteasome degradation, the relationship between proteolysis and transcriptional regulation is incompletely understood. Based on studies primarily focusing on the C-terminal ligand-binding and AF-2 transactivation domains, an assembly of an active transcriptional complex has been proposed to signal ERα proteolysis that is in turn necessary for its transcriptional activity. Here, we investigated the role of other regions of ERα and identified S118 within the N-terminal AF-1 transactivation domain as an additional element for regulating estrogen-induced ubiquitination and degradation of ERα. Significantly, different S118 mutants revealed that degradation and transcriptional activity of ERα are mechanistically separable functions of ERα. We find that proteolysis of ERα correlates with the ability of ERα mutants to recruit specific ubiquitin ligases regardless of the recruitment of other transcription-related factors to endogenous model target genes. Thus, our findings indicate that the AF-1 domain performs a previously unrecognized and important role in controlling ligand-induced receptor degradation which permits the uncoupling of estrogen-regulated ERα proteolysis and transcription.

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