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1.
Methods Mol Biol ; 2589: 361-376, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36255637

RESUMO

Experiments determining the chromatin association of histone acetylases (HATs) and deacetylases (HDACs) at the genome-wide level provide precise maps of locus occupancy, but do not allow conclusions on the functional consequences of this locus-specific enrichment. Here we describe a protocol that allows tethering of HATs or HDACs to specific genomic loci upon fusion with a fluorescent protein and a DNA-binding protein such as the E. coli Lac repressor (LacI), which binds to genomically inserted lac operon sequences (lacO) via DNA/protein interactions. Integration of these lacO sequences into a genomic region of interest allows to monitor the functional consequences of HAT/HDAC targeting on chromatin (de)compaction, histone modification, and interaction with other proteins by quantitative light microscopy, as described here. As DNA-binding of LacI can be tightly controlled by the addition of galactose-derivatives, this method also allows to monitor the effects of locus-specific recruitment in a time-resolved manner.


Assuntos
Cromatina , Histona Acetiltransferases , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismo , Cromatina/genética , Repressores Lac/genética , Histonas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Galactose , Histona Desacetilases/metabolismo , DNA/genética , DNA/metabolismo , Acetilação , Acetiltransferases/metabolismo
2.
Nucleic Acids Res ; 50(18): 10586-10600, 2022 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-36200834

RESUMO

Type II toxin-antitoxin (TA) systems are widely distributed in bacterial and archaeal genomes and are involved in diverse critical cellular functions such as defense against phages, biofilm formation, persistence, and virulence. GCN5-related N-acetyltransferase (GNAT) toxin, with an acetyltransferase activity-dependent mechanism of translation inhibition, represents a relatively new and expanding family of type II TA toxins. We here describe a group of GNAT-Xre TA modules widely distributed among Pseudomonas species. We investigated PacTA (one of its members encoded by PA3270/PA3269) from Pseudomonas aeruginosa and demonstrated that the PacT toxin positively regulates iron acquisition in P. aeruginosa. Notably, other than arresting translation through acetylating aminoacyl-tRNAs, PacT can directly bind to Fur, a key ferric uptake regulator, to attenuate its DNA-binding affinity and thus permit the expression of downstream iron-acquisition-related genes. We further showed that the expression of the pacTA locus is upregulated in response to iron starvation and the absence of PacT causes biofilm formation defect, thereby attenuating pathogenesis. Overall, these findings reveal a novel regulatory mechanism of GNAT toxin that controls iron-uptake-related genes and contributes to bacterial virulence.


Assuntos
Antitoxinas , Toxinas Bacterianas , Acetiltransferases/metabolismo , Antitoxinas/genética , Antitoxinas/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , DNA/metabolismo , Regulação Bacteriana da Expressão Gênica , Homeostase/genética , Ferro/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo
3.
Int J Mol Sci ; 23(19)2022 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-36232610

RESUMO

During viral infection, both host and viral proteins undergo post-translational modifications (PTMs), including phosphorylation, ubiquitination, methylation, and acetylation, which play critical roles in viral replication, pathogenesis, and host antiviral responses. Protein acetylation is one of the most important PTMs and is catalyzed by a series of acetyltransferases that divert acetyl groups from acetylated molecules to specific amino acid residues of substrates, affecting chromatin structure, transcription, and signal transduction, thereby participating in the cell cycle as well as in metabolic and other cellular processes. Acetylation of host and viral proteins has emerging roles in the processes of virus adsorption, invasion, synthesis, assembly, and release as well as in host antiviral responses. Methods to study protein acetylation have been gradually optimized in recent decades, providing new opportunities to investigate acetylation during viral infection. This review summarizes the classification of protein acetylation and the standard methods used to map this modification, with an emphasis on viral and host protein acetylation during viral infection.


Assuntos
Antivirais , Viroses , Acetilação , Acetiltransferases/metabolismo , Aminoácidos/metabolismo , Cromatina , Humanos , Processamento de Proteína Pós-Traducional , Proteínas Virais/metabolismo
4.
J Cell Biol ; 221(11)2022 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-36222836

RESUMO

Spatiotemporally dynamic microtubule acetylation underlies diverse physiological and pathological events. Despite its ubiquity, the molecular mechanisms that regulate the sole microtubule acetylating agent, α-tubulin-N-acetyltransferase-1 (α-TAT1), remain obscure. Here, we report that dynamic intracellular localization of α-TAT1 along with its catalytic activity determines efficiency of microtubule acetylation. Specifically, we newly identified a conserved signal motif in the intrinsically disordered C-terminus of α-TAT1, consisting of three competing regulatory elements-nuclear export, nuclear import, and cytosolic retention. Their balance is tuned via phosphorylation by CDK1, PKA, and CK2, and dephosphorylation by PP2A. While the unphosphorylated form binds to importins and resides both in cytosol and nucleus, the phosphorylated form binds to specific 14-3-3 adapters and accumulates in the cytosol for maximal substrate access. Unlike other molecules with a similar phospho-regulated signal motif, α-TAT1 uniquely uses the nucleus as a hideout. This allosteric spatial regulation of α-TAT1 function may help uncover a spatiotemporal code of microtubule acetylation in normal and aberrant cell behavior.


Assuntos
Acetiltransferases , Microtúbulos , Tubulina (Proteína) , Acetilação , Acetiltransferases/genética , Acetiltransferases/metabolismo , Transporte Ativo do Núcleo Celular , Citosol , Proteínas Intrinsicamente Desordenadas/metabolismo , Carioferinas/metabolismo , Microtúbulos/metabolismo , Fosforilação , Tubulina (Proteína)/metabolismo
5.
Biomed Res Int ; 2022: 1616370, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36172487

RESUMO

To determine the clinical prognostic significance of lncRNA MCM3AP-AS1 in colorectal cancer (CRC) and its preliminary mechanism, 43 CRC patients and 48 healthy individuals were analyzed. Peripheral blood MCM3AP-AS1 was quantified via qRT-PCR in CRC patients at admission and 2 h after surgery and in healthy individuals. Human colon cancer cells (HCT116 and SW480) were transfected with shRNAs targeting upregulation of MCM3AP-AS1 expression (named as sh-MCM3AP-AS1 group) and corresponding negative RNAs (named as sh-MCM3AP-AS1 group). Additionally, the cells were then treated either with 50 mM of the VEGF-specific inhibitor PTK787 (Selleck, USA) (named as inhibition group) or normal saline as a control (named as control group). Before therapy, CRC patients presented a higher MCM3AP-AS1 level than healthy individuals (P < 0.05), and the sensitivity and specificity of MCM3AP-AS1 in predicting the occurrence of CRC were 65.12% and 83.33%, respectively (P < 0.001). After therapy, CRC patients presented a decrease in MCM3AP-AS1 levels, and recurrence was higher in patients who died (P < 0.05). Additionally, the high MCM3AP-AS1 expression group presented a higher mortality than the low MCM3AP-AS1 expression group (P < 0.05). In an in vitro assay, CRC cells showed a higher MCM3AP-AS1 level than CCD-18Co cells, and the sh-MCM3AP-AS1 group presented decreased cell proliferation and invasiveness, whereas the levels apoptosis-associated proteins were increased (P < 0.05). Moreover, the VEGF and VEGFR2 mRNA levels were increased in CRC cells, and VEGF/VEGFR2 pathway-associated proteins were inhibited in the sh-MCM3AP-AS1 group (P < 0.05). Moreover, treatment with PTK787 decreased cell proliferation and invasivness but increased the levels of apoptosis-associated proteins (P < 0.05).


Assuntos
Neoplasias Colorretais , RNA Longo não Codificante , Acetiltransferases/genética , Acetiltransferases/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Neoplasias Colorretais/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Prognóstico , RNA Longo não Codificante/metabolismo , RNA Mensageiro , Solução Salina , Fator A de Crescimento do Endotélio Vascular/metabolismo
6.
Methods Mol Biol ; 2550: 33-43, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36180675

RESUMO

Melatonin is synthesized and secreted by the pineal gland in mammals. Its synthesis is triggered at night by norepinephrine released in the interstices of the gland. This nocturnal production is dependent on the transcription, translation, and/or activation of the enzymes arylalkylamine-N-acetyltransferase (AANAT), acetylserotonin O-methyltransferase (ASMT), and tryptophan hydroxylase (TPH). In this chapter, the methodology for the analysis of AANAT, ASMT, and TPH activities by radiometric assays will be presented. Several papers were published by our group utilizing these methodologies, evaluating the enzymes modulation by voltage-gated calcium channels, angiotensin II, insulin, anhydroecgonine methyl ester (AEME, crack-cocaine product), ethanol, monosodium glutamate (MSG), signaling pathways such as NFkB, and pathophysiological conditions such as diabetes.


Assuntos
Cocaína , Insulinas , Melatonina , Acetilserotonina O-Metiltransferasa/metabolismo , Acetiltransferases/metabolismo , Angiotensina II/metabolismo , Animais , Canais de Cálcio , Etanol , Mamíferos/metabolismo , Melatonina/metabolismo , Norepinefrina , Glutamato de Sódio , Triptofano Hidroxilase/genética , Triptofano Hidroxilase/metabolismo
7.
Nat Commun ; 13(1): 5435, 2022 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-36114200

RESUMO

Covalent attachment of ubiquitin (Ub) to proteins is a highly versatile posttranslational modification. Moreover, Ub is not only a modifier but itself is modified by phosphorylation and lysine acetylation. However, the functional consequences of Ub acetylation are poorly understood. By generation and comprehensive characterization of all seven possible mono-acetylated Ub variants, we show that each acetylation site has a particular impact on Ub structure. This is reflected in selective usage of the acetylated variants by different E3 ligases and overlapping but distinct interactomes, linking different acetylated variants to different cellular pathways. Notably, not only electrostatic but also steric effects contribute to acetylation-induced changes in Ub structure and, thus, function. Finally, we provide evidence that p300 acts as a position-specific Ub acetyltransferase and HDAC6 as a general Ub deacetylase. Our findings provide intimate insights into the structural and functional consequences of Ub acetylation and highlight the general importance of Ub acetylation.


Assuntos
Lisina , Ubiquitina , Acetilação , Acetiltransferases/metabolismo , Lisina/metabolismo , Processamento de Proteína Pós-Traducional , Eletricidade Estática , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
8.
mBio ; 13(5): e0212322, 2022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36069442

RESUMO

Upon nitrogen starvation, the basidiomycete Ustilago maydis, which causes smut disease on corn, secretes amphipathic glycolipids, including mannosylerythritol lipids (MELs). MELs consist of a carbohydrate core whose mannosyl moiety is both acylated with fatty acids of different lengths and acetylated. Here, we report the transport of MELs into and out of the cell depending on the transport protein Mmf1, which belongs to the major facilitator superfamily. Analysis of mmf1 mutants and mutants lacking the acetyltransferase Mat1 revealed that Mmf1 is necessary for the export of acetylated MELs, while MELs without an acetyl group are secreted independently of this transporter. Upon deletion of mmf1, we detected novel MEL species lacking the acyl side chain at C-3'. With the help of feeding experiments, we demonstrate that MELs are taken up by U. maydis in an mmf1-independent manner. This leads to catabolism or rearrangement of acetyl and acyl side groups and subsequent secretion. The catabolism of MELs involves the presence of Mac2, an enzyme required for MEL biosynthesis. In cocultivation experiments, mutual exchange of MELs between different mutants was observed. Thus, we propose a novel function for fungal glycolipids as an external carbon storage. IMPORTANCE Fungi produce and secrete various secondary metabolites that can act as weapons against competitors, help in accessing nutrients, or assist in development and communication. One group of secondary metabolites are surface-active glycolipids, which have significant biotechnological potential as biodegradable detergents. While the biosynthesis of several fungal biosurfactants is well characterized, their biological functions and transport routes are less understood. We developed a cocultivation assay to show that a class of glycolipids from Ustilago maydis called mannosylerythritol lipids (MELs) can be exchanged between cells and modified or even degraded by recipient cells. Feeding assays with purified MELs led to similar results. These data provide insight into the surprising biological role of MELs as putative external carbon sources. Applying feeding and cocultivation experiments on MEL biosynthesis mutants turned out to be a valuable strategy for systematically studying the import routes and degradation pathways of glycolipids. By using these assays, we demonstrate the function of the transport protein Mmf1 as a specific exporter of acetylated MELs. We propose that these assays may be applied more generally, thereby opening novel areas of research.


Assuntos
Detergentes , Ustilaginales , Detergentes/metabolismo , Glicolipídeos/metabolismo , Ustilaginales/genética , Ustilaginales/metabolismo , Acetiltransferases/metabolismo , Ácidos Graxos/metabolismo , Nitrogênio/metabolismo , Carbono/metabolismo , Proteínas de Transporte/metabolismo , Tensoativos/química , Tensoativos/metabolismo
9.
ACS Chem Biol ; 17(10): 2923-2935, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36122366

RESUMO

Siderophores produced via nonribosomal peptide synthetase (NRPS) pathways serve as critical virulence factors for many pathogenic bacteria. Improved knowledge of siderophore biosynthesis guides the development of inhibitors, vaccines, and other therapeutic strategies. Fimsbactin A is a mixed ligand siderophore derived from human pathogenic Acinetobacter baumannii that contains phenolate-oxazoline, catechol, and hydroxamate metal chelating groups branching from a central l-Ser tetrahedral unit via amide and ester linkages. Fimsbactin A is derived from two molecules of l-Ser, two molecules of 2,3-dihydroxybenzoic acid (DHB), and one molecule of l-Orn and is a product of the fbs biosynthetic operon. Here, we report the complete in vitro reconstitution of fimsbactin A biosynthesis in a cell-free system using purified enzymes. We demonstrate the conversion of l-Orn to N1-acetyl-N1-hydroxy-putrescine (ahPutr) via ordered action of FbsJ (decarboxylase), FbsI (flavin N-monooxygenase), and FbsK (N-acetyltransferase). We achieve conversion of l-Ser, DHB, and l-Orn to fimsbactin A using FbsIJK in combination with the NRPS modules FbsEFGH. We also demonstrate chemoenzymatic conversion of synthetic ahPutr to fimsbactin A using FbsEFGH and establish the substrate selectivity for the NRPS adenylation domains in FbsH (DHB) and FbsF (l-Ser). We assign a role for the type II thioesterase FbsM in producing the shunt metabolite 2-(2,3-dihydroxyphenyl)-4,5-dihydrooxazole-4-carboxylic acid (DHB-oxa) via cleavage of the corresponding thioester intermediate that is tethered to NRPS peptidyl carrier domains during biosynthetic assembly. We propose a mechanism for branching NRPS-derived peptides via amide and ester linkages via the dynamic equilibration of N-DHB-Ser and O-DHB-Ser thioester intermediates via hydrolysis of DHB-oxa thioester intermediates. We also propose a genetic signature for NRPS "branching" in the presence of a terminating C-T-C motif (FbsG).


Assuntos
Acinetobacter baumannii , Carboxiliases , Humanos , Sideróforos/metabolismo , Acinetobacter baumannii/metabolismo , Putrescina/metabolismo , Ligantes , Peptídeo Sintases/metabolismo , Catecóis/metabolismo , Fatores de Virulência/metabolismo , Hidroxibenzoatos/química , Amidas/metabolismo , Ésteres/metabolismo , Flavinas/metabolismo , Oxigenases de Função Mista/metabolismo , Acetiltransferases/metabolismo , Carboxiliases/metabolismo , Peptídeos/metabolismo
10.
Nucleic Acids Res ; 50(17): 9797-9813, 2022 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-36095118

RESUMO

Chromatin complexes control a vast number of epigenetic developmental processes. Filamentous fungi present an important clade of microbes with poor understanding of underlying epigenetic mechanisms. Here, we describe a chromatin binding complex in the fungus Aspergillus nidulans composing of a H3K4 histone demethylase KdmB, a cohesin acetyltransferase (EcoA), a histone deacetylase (RpdA) and a histone reader/E3 ligase protein (SntB). In vitro and in vivo evidence demonstrate that this KERS complex is assembled from the EcoA-KdmB and SntB-RpdA heterodimers. KdmB and SntB play opposing roles in regulating the cellular levels and stability of EcoA, as KdmB prevents SntB-mediated degradation of EcoA. The KERS complex is recruited to transcription initiation start sites at active core promoters exerting promoter-specific transcriptional effects. Interestingly, deletion of any one of the KERS subunits results in a common negative effect on morphogenesis and production of secondary metabolites, molecules important for niche securement in filamentous fungi. Consequently, the entire mycotoxin sterigmatocystin gene cluster is downregulated and asexual development is reduced in the four KERS mutants. The elucidation of the recruitment of epigenetic regulators to chromatin via the KERS complex provides the first mechanistic, chromatin-based understanding of how development is connected with small molecule synthesis in fungi.


Assuntos
Aspergillus nidulans , Cromatina , Acetiltransferases/metabolismo , Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Cromatina/genética , Cromatina/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Genes Reguladores , Histona Desacetilases/metabolismo , Histona Desmetilases/metabolismo , Histonas/genética , Histonas/metabolismo , Esterigmatocistina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
11.
Int J Mol Sci ; 23(18)2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36142717

RESUMO

Most eukaryotic proteins are N-terminally acetylated by a set of Nα acetyltransferases (NATs). This ancient and ubiquitous modification plays a fundamental role in protein homeostasis, while mutations are linked to human diseases and phenotypic defects. In particular, Naa50 features species-specific differences, as it is inactive in yeast but active in higher eukaryotes. Together with NatA, it engages in NatE complex formation for cotranslational acetylation. Here, we report Naa50 homologs from the filamentous fungi Chaetomium thermophilum and Neurospora crassa with significant N- and C-terminal extensions to the conserved GNAT domain. Structural and biochemical analyses show that CtNaa50 shares the GNAT structure and substrate specificity with other homologs. However, in contrast to previously analyzed Naa50 proteins, it does not form NatE. The elongated N-terminus increases Naa50 thermostability and binds to dynein light chain protein 1, while our data suggest that conserved positive patches in the C-terminus allow for ribosome binding independent of NatA. Our study provides new insights into the many facets of Naa50 and highlights the diversification of NATs during evolution.


Assuntos
Acetiltransferase N-Terminal E , Acetiltransferases N-Terminal , Acetilação , Acetiltransferases/metabolismo , Dineínas/metabolismo , Humanos , Acetiltransferase N-Terminal E/química , Acetiltransferases N-Terminal/metabolismo , Saccharomyces cerevisiae/metabolismo
12.
PLoS Genet ; 18(9): e1010352, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36107838

RESUMO

General control nonderepressible 5 protein (Gcn5) and its homologs, including p300/CBP-associated factor (PCAF), are lysine acetyltransferases that modify both histone and non-histone proteins using acetyl coenzyme A as a donor substrate. While decades of studies have uncovered a vast network of cellular processes impacted by these acetyltransferases, including gene transcription and metabolism, far less is known about how these enzymes are themselves regulated. In this review, we summarize the type and functions of posttranslational modifications proposed to control Gcn5 in both yeast and human cells. We further outline common themes, open questions, and strategies to guide future work.


Assuntos
Acetiltransferases/metabolismo , Histonas , Processamento de Proteína Pós-Traducional , Acetilcoenzima A/genética , Acetilcoenzima A/metabolismo , Acetilação , Histonas/genética , Histonas/metabolismo , Humanos , Processamento de Proteína Pós-Traducional/genética
13.
Aging Cell ; 21(9): e13675, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35962576

RESUMO

The master epigenetic regulator lysine acetyltransferase (KAT) p300/CBP plays a pivotal role in neuroplasticity and cognitive functions. Recent evidence has shown that in several neurodegenerative diseases, including Alzheimer's disease (AD), the expression level and function of p300/CBP are severely compromised, leading to altered gene expression causing pathological conditions. Here, we show that p300/CBP activation by a small-molecule TTK21, conjugated to carbon nanosphere (CSP) ameliorates Aß-impaired long-term potentiation (LTP) induced by high-frequency stimulation, theta burst stimulation, and synaptic tagging/capture (STC). This functional rescue was correlated with CSP-TTK21-induced changes in transcription and translation. Mechanistically, we observed that the expression of a large number of synaptic plasticity- and memory-related genes was rescued, presumably by the restoration of p300/CBP mediated acetylation. Collectively, these results suggest that small-molecule activators of p300/CBP could be a potential therapeutic molecule for neurodegenerative diseases like AD.


Assuntos
Nanosferas , Acetilação , Acetiltransferases/metabolismo , Carbono/metabolismo , Glucose/metabolismo , Hipocampo/metabolismo , Histonas/metabolismo , Células Piramidais/metabolismo
14.
Mol Med Rep ; 26(4)2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35920180

RESUMO

Chronic thromboembolic pulmonary hypertension (CTEPH) is a leading cause of pulmonary hypertension. The present study investigated the mechanisms of long non­coding RNA growth arrest­specific transcript 5 (GAS5) on spermidine (SP)­induced autophagy. Pulmonary artery endothelial cells (PAECs) were collected from patients with CTEPH and the rat model. Immunofluorescence, Western blots, reverse transcription­quantitative polymerase chain reaction, bioinformatics, rapid amplification of cDNA ends assays, luciferase reporter assays, RNA­binding protein immunoprecipitation assays, GFP­LC3 adenoviruses, tfLC3 assays and transmission electron microscopy were performed. The results revealed that SP­induced autophagy increased GAS5 in PAECs. The upregulation of GAS5 enhanced and the downregulation of GAS5 reversed the roles of SP in PAECs. Furthermore, GAS5 promoted SP­induced autophagy in PAECs by targeting miRNA­31­5p. The miRNA­31­5p mimic suppressed and the inhibitor promoted SP­induced autophagy. Furthermore, N­Acetyltransferase 8 Like (NAT8L) was a target gene of miRNA­31­5p and knockdown of NAT8L inhibited the autophagic levels of PAECs. In vivo, SP treatment decreased miRNA­31­5p and increased NAT8L levels, which was reversed by the knockdown of GAS5. The downregulation of GAS5 abolished the stimulatory role of SP in PAECs of CTEPH rats. In conclusion, GAS5 promoted SP­induced autophagy through miRNA­31­5p/NAT8L signaling pathways in vitro and in vivo and GAS5 may be a promising molecular marker for therapies of CTEPH.1.


Assuntos
Acetiltransferases , Hipertensão Pulmonar , MicroRNAs , RNA Longo não Codificante , Acetiltransferases/genética , Acetiltransferases/metabolismo , Animais , Autofagia , Células Endoteliais/metabolismo , MicroRNAs/metabolismo , Artéria Pulmonar/metabolismo , RNA Longo não Codificante/metabolismo , Ratos , Espermidina
15.
J Hematol Oncol ; 15(1): 112, 2022 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-35978332

RESUMO

BACKGROUND: Although a substantial increase in the survival of patients with other cancers has been observed in recent decades, pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest diseases. No effective screening approach exists. METHODS: Differential exosomal long noncoding RNAs (lncRNAs) isolated from the serum of patients with PDAC and healthy individuals were profiled to screen for potential markers in liquid biopsies. The functions of LINC00623 in PDAC cell proliferation, migration and invasion were confirmed through in vivo and in vitro assays. RNA pulldown, RNA immunoprecipitation (RIP) and coimmunoprecipitation (Co-IP) assays and rescue experiments were performed to explore the molecular mechanisms of the LINC00623/NAT10 signaling axis in PDAC progression. RESULTS: A novel lncRNA, LINC00623, was identified, and its diagnostic value was confirmed, as it could discriminate patients with PDAC from patients with benign pancreatic neoplasms and healthy individuals. Moreover, LINC00623 was shown to promote the tumorigenicity and migratory capacity of PDAC cells in vitro and in vivo. Mechanistically, LINC00623 bound to N-acetyltransferase 10 (NAT10) and blocked its ubiquitination-dependent degradation by recruiting the deubiquitinase USP39. As a key regulator of N4-acetylcytidine (ac4C) modification of mRNA, NAT10 was demonstrated to maintain the stability of oncogenic mRNAs and promote their translation efficiency through ac4C modification. CONCLUSIONS: Our data revealed the role of LINC00623/NAT10 signaling axis in PDAC progression, showing that it is a potential biomarker and therapeutic target for PDAC.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , RNA Longo não Codificante , Acetiltransferases/genética , Acetiltransferases/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Citidina/análogos & derivados , Regulação Neoplásica da Expressão Gênica , Humanos , Acetiltransferases N-Terminal/genética , Acetiltransferases N-Terminal/metabolismo , Invasividade Neoplásica/patologia , Neoplasias Pancreáticas/patologia , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , RNA Mensageiro , Proteases Específicas de Ubiquitina
16.
Chem Res Toxicol ; 35(10): 1747-1765, 2022 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-36044734

RESUMO

Nitro group containing xenobiotics include drugs, cancer chemotherapeutic agents, carcinogens (e.g., nitroarenes and aristolochic acid) and explosives. The nitro group undergoes a six-electron reduction to form sequentially the nitroso-, N-hydroxylamino- and amino-functional groups. These reactions are catalyzed by nitroreductases which, rather than being enzymes with this sole function, are enzymes hijacked for their propensity to donate electrons to the nitro group either one at a time via a radical mechanism or two at time via the equivalent of a hydride transfer. These enzymes include: NADPH-dependent flavoenzymes (NADPH: P450 oxidoreductase, NAD(P)H-quinone oxidoreductase), P450 enzymes, oxidases (aldehyde oxidase, xanthine oxidase) and aldo-keto reductases. The hydroxylamino group once formed can undergo conjugation reactions with acetate or sulfate catalyzed by N-acetyltransferases or sulfotransferases, respectively, leading to the formation of intermediates containing a good leaving group which in turn can generate a nitrenium or carbenium ion for covalent DNA adduct formation. The intermediates in the reduction sequence are also prone to oxidation and produce reactive oxygen species. As a consequence, many nitro-containing xenobiotics can be genotoxic either by forming stable covalent adducts or by oxidatively damaging DNA. This review will focus on the general chemistry of nitroreduction, the enzymes responsible, the reduction of xenobiotic substrates, the regulation of nitroreductases, the ability of nitrocompounds to form DNA adducts and act as mutagens as well as some future directions.


Assuntos
Poluentes Ambientais , Substâncias Explosivas , Acetiltransferases/metabolismo , Aldeídos , Aldo-Ceto Redutases/metabolismo , Carcinógenos , Adutos de DNA , Redes e Vias Metabólicas , Mutagênicos/metabolismo , NAD/metabolismo , NAD(P)H Desidrogenase (Quinona)/metabolismo , NADP/metabolismo , Quinonas , Espécies Reativas de Oxigênio , Sulfatos , Sulfotransferases/metabolismo , Xantina Oxidase/metabolismo , Xenobióticos
17.
mBio ; 13(5): e0178922, 2022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36040031

RESUMO

The antibiotic desertomycin A and its previously undescribed inactive N-succinylated analogue, desertomycin X, were isolated from Streptomyces sp. strain YIM 121038. Genome sequencing and analysis readily identified the desertomycin biosynthetic gene cluster (BGC), which lacked genes encoding acyltransferases that would account for desertomycin X formation. Scouting the genome for putative N-acyltransferase genes led to the identification of a candidate within a cryptic siderophore BGC (csb) encoding a putative homologue of the N6'-hydroxylysine acetyltransferase IucB. Expression of the codon-optimized gene designated csbC in Escherichia coli yielded the recombinant protein that was able to N-succinylate desertomycin A as well as several other structurally distinct antibiotics harboring amino groups. Some antibiotics were rendered antibiotically inactive due to the CsbC-catalyzed succinylation in vitro. Unlike many known N-acyltransferases involved in antibiotic resistance, CsbC could not efficiently acetylate the same antibiotics. When expressed in E. coli, CsbC provided low-level resistance to kanamycin and ampicillin, suggesting that it may play a role in antibiotic resistance in natural habitats, where the concentration of antibiotics is usually low. IMPORTANCE In their natural habitats, bacteria encounter a plethora of organic compounds, some of which may be represented by antibiotics produced by certain members of the microbial community. A number of antibiotic resistance mechanisms have been described, including those specified by distinct genes encoding proteins that degrade, modify, or expel antibiotics. In this study, we report identification and characterization of an enzyme apparently involved in the biosynthesis of a siderophore, but also having the ability of modify and thereby inactivate a wide variety of structurally diverse antibiotics. This discovery sheds light on additional capabilities of bacteria to withstand antibiotic treatment and suggests that enzymes involved in secondary metabolism may have an additional function in the natural environment.


Assuntos
Streptomyces , Streptomyces/genética , Streptomyces/metabolismo , Antibacterianos/metabolismo , Metabolismo Secundário , Sideróforos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Hidroxilisina/genética , Hidroxilisina/metabolismo , Família Multigênica , Acetiltransferases/genética , Acetiltransferases/metabolismo , Proteínas Recombinantes/genética , Ampicilina , Canamicina/metabolismo
18.
mBio ; 13(5): e0201322, 2022 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-36043788

RESUMO

Lysine acetylation, a ubiquitous and dynamic regulatory posttranslational modification (PTM), affects hundreds of proteins across all domains of life. In bacteria, lysine acetylation can be found in many essential pathways, and it is also crucial for bacterial virulence. However, the biological significance of lysine acetylation events to bacterial virulence factors remains poorly characterized. In Streptococcus mutans, the acetylome profiles help identify several lysine acetylation sites of lactate dehydrogenase (LDH), which catalyzes the conversion of pyruvate to lactic acid, causing the deterioration of teeth. We investigated the regulatory mechanism of LDH acetylation and characterized the effect of LDH acetylation on its function. We overexpressed the 15 Gcn5 N-acetyltransferases (GNAT) family members in S. mutans and showed that the acetyltransferase ActA impaired its acidogenicity by acetylating LDH. Additionally, enzymatic acetyltransferase reactions demonstrated that purified ActA could acetylate LDH in vitro, and 10 potential lysine acetylation sites of LDH were identified by mass spectrometry, 70% of which were also detected in vivo. We further demonstrated that the lysine acetylation of LDH inhibited its enzymatic activity, and a subsequent rat caries model showed that ActA impaired the cariogenicity of S. mutans. Collectively, we demonstrated that ActA, the first identified and characterized acetyltransferase in S. mutans, acetylated the LDH enzymatically and inhibited its enzymatic activity, thereby providing a starting point for the further analysis of the biological significance of lysine acetylation in the virulence of S. mutans. IMPORTANCE Lysine acetylation, a dynamic regulatory posttranslational modification, remains poorly characterized in bacteria. Hundreds of proteins have been identified to be acetylated in bacteria, with advances made in acetylome analyses. However, the regulatory mechanisms and functional significance of the majority of these acetylated proteins remain unclear. We analyzed the acetylome profiles of Streptococcus mutans and found that lactate dehydrogenase (LDH) contains several lysine acetylation sites. We also demonstrated that the acetyltransferase ActA, a member of the Gcn5 N-acetyltransferases (GNAT) family in S. mutans, acetylated LDH, inhibited its enzymatic ability to catalyze the conversion of pyruvate to lactic acid, and impaired its cariogenicity in a rat caries model. Therefore, LDH acetylation might be a potential target that can be exploited in the design of novel therapeutics to prevent dental caries.


Assuntos
Cárie Dentária , Streptococcus mutans , Ratos , Animais , Acetilação , Streptococcus mutans/genética , Streptococcus mutans/metabolismo , Lisina/metabolismo , L-Lactato Desidrogenase/genética , L-Lactato Desidrogenase/metabolismo , Processamento de Proteína Pós-Traducional , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Acetiltransferases/genética , Acetiltransferases/metabolismo , Ácido Láctico , Piruvatos
19.
Chem Res Toxicol ; 35(10): 1881-1892, 2022 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-35976686

RESUMO

p-Phenylenediamine (PPD) has been classified as a strong skin allergen, but when it comes to toxicological concerns, benzoquinone diamine (BQDI), the primary oxidation derivative of PPD, is frequently considered and was shown to covalently bind nucleophilic residues on model peptides. However, tests in solution are far from providing a reliable model, as the cutaneous metabolism of PPD is not covered. We now report the synthesis of two 13C substituted isotopomers of PPD, 1,4-(13C)p-phenylenediamine 1 and 2,5-(13C)p-phenylenediamine 2, and the investigation of their reactivity in reconstructed human epidermis (RHE) using the high resolution magic angle spinning (HRMAS) NMR technique. RHE samples were first treated with 1 or 2 and incubated for 1 to 48 h. Compared to the control, spectra clearly showed only the signals of 1 or 2 gradually decreasing with time to disappear after 48 h of incubation. However, the culture media of RHE incubated with 1 for 1 and 24 h, respectively, showed the presence of both monoacetylated- and diacetylated-PPD as major products. Therefore, the acetylation reaction catalyzed by N-acetyltransferase (NAT) enzymes appeared to be the main process taking place in RHE. With the aim of increasing the reactivity by oxidation, 1 and 2 were treated with 0.5 equiv of H2O2 prior to their application to RHE and incubated for different times. Under these conditions, new peaks having close chemical shifts to those of PPD-cysteine adducts previously observed in solution were detected. Under such oxidative conditions, we were thus able to detect and quantify cysteine adducts in RHE (maximum of 0.2 nmol/mg of RHE at 8 h of incubation) while no reaction with other nucleophilic amino acid residues could be observed.


Assuntos
Cisteína , Peróxido de Hidrogênio , Acetiltransferases/metabolismo , Alérgenos , Aminoácidos/metabolismo , Benzoquinonas/metabolismo , Meios de Cultura , Cisteína/química , Epiderme/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Fenilenodiaminas/metabolismo
20.
Sci Rep ; 12(1): 14003, 2022 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-35977998

RESUMO

Microtubules are fundamental elements of neuronal structure and function. They are dynamic structures formed from protofilament chains of α- and ß-tubulin heterodimers. Acetylation of the lysine 40 (K40) residue of α-tubulin protects microtubules from mechanical stresses by imparting structural elasticity. The enzyme responsible for this acetylation event is MEC-17/αTAT1. Despite its functional importance, however, the consequences of altered MEC-17/αTAT1 levels on neuronal structure and function are incompletely defined. Here we demonstrate that overexpression or loss of MEC-17, or of its functional paralogue ATAT-2, causes a delay in synaptic branch extension, and defective synaptogenesis in the mechanosensory neurons of Caenorhabditis elegans. Strikingly, by adulthood, the synaptic branches in these animals are lost, while the main axon shaft remains mostly intact. We show that MEC-17 and ATAT-2 regulate the stability of the synaptic branches largely independently from their acetyltransferase domains. Genetic analyses reveals novel interactions between both mec-17 and atat-2 with the focal adhesion gene zyx-1/Zyxin, which has previously been implicated in actin remodelling. Together, our results reveal new, acetylation-independent roles for MEC-17 and ATAT-2 in the development and maintenance of neuronal architecture.


Assuntos
Proteínas de Caenorhabditis elegans , Acetilação , Acetiltransferases/genética , Acetiltransferases/metabolismo , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Microtúbulos/metabolismo , Tubulina (Proteína)/metabolismo
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