scholarly journals NAA10 p.(D10G) and NAA10 p.(L11R) Variants Hamper Formation of the NatA N-Terminal Acetyltransferase Complex

2020 ◽  
Vol 21 (23) ◽  
pp. 8973
Author(s):  
Nina McTiernan ◽  
Christine Darbakk ◽  
Rasmus Ree ◽  
Thomas Arnesen
Keyword(s):  
Amino Acids ◽  
Functional Analysis ◽  
Catalytic Activity ◽  
Complex Formation ◽  
Genetic Disease ◽  
De Novo ◽  
Disease Mechanisms ◽  
Functional Consequences

The majority of the human proteome is subjected to N-terminal (Nt) acetylation catalysed by N-terminal acetyltransferases (NATs). The NatA complex is composed of two core subunits—the catalytic subunit NAA10 and the ribosomal anchor NAA15. Furthermore, NAA10 may also have catalytic and non-catalytic roles independent of NatA. Several inherited and de novo NAA10 variants have been associated with genetic disease in humans. In this study, we present a functional analysis of two de novo NAA10 variants, c.29A>G p.(D10G) and c.32T>G p.(L11R), previously identified in a male and a female, respectively. Both of these neighbouring amino acids are highly conserved in NAA10. Immunoprecipitation experiments revealed that both variants hamper complex formation with NAA15 and are thus likely to impair NatA-mediated Nt-acetylation in vivo. Despite their common impact on NatA formation, in vitro Nt-acetylation assays showed that the variants had opposing impacts on NAA10 catalytic activity. While NAA10 c.29A>G p.(D10G) exhibits normal intrinsic NatA activity and reduced monomeric NAA10 NAT activity, NAA10 c.32T>G p.(L11R) displays reduced NatA activity and normal NAA10 NAT activity. This study expands the scope of research into the functional consequences of NAA10 variants and underlines the importance of understanding the diverse cellular roles of NAA10 in disease mechanisms.

scholarly journals Set2-Dependent K36 Methylation Is Regulated by Novel Intratail Interactions within H3

2009 ◽  
Vol 29 (24) ◽  
pp. 6413-6426 ◽  
Author(s):  
James N. Psathas ◽  
Suting Zheng ◽  
Song Tan ◽  
Joseph C. Reese
Keyword(s):  
Amino Acids ◽  
Catalytic Activity ◽  
Chromatin Remodeling ◽  
Posttranslational Modifications ◽  
Active Site ◽  
Transcription Initiation ◽  
Gene Activation ◽  
N Terminus

ABSTRACT Posttranslational modifications to histones have been studied extensively, but the requirement for the residues within the tails for different stages of transcription is less clear. Using RNR3 as a model, we found that the residues within the N terminus of H3 are predominantly required for steps after transcription initiation and chromatin remodeling. Specifically, deleting as few as 20 amino acids, or substituting glutamines for lysines in the tail, greatly impaired K36 methylation by Set2. The mutations to the tail described here preserve the residues predicted to fill the active site of Set2, and the deletion mimics the recently described cleavage of the H3 tail that occurs during gene activation. Importantly, maintaining the charge of the unmodified tail by arginine substitutions preserves Set2 function in vivo. The H3 tail is dispensable for Set2 recruitment to genes but is required for the catalytic activity of Set2 in vitro. We propose that Set2 activity is controlled by novel intratail interactions which can be influenced by modifications and changes to the structure of the H3 tail to control the dynamics and localization of methylation during elongation.

scholarly journals VP8, the Major Tegument Protein of Bovine Herpesvirus 1, Interacts with Cellular STAT1 and Inhibits Interferon Beta Signaling

2016 ◽  
Vol 90 (10) ◽  
pp. 4889-4904 ◽  
Author(s):  
Sharmin Afroz ◽  
Robert Brownlie ◽  
Michel Fodje ◽  
Sylvia van Drunen Littel-van den Hurk
Keyword(s):  
Amino Acids ◽  
Interferon Beta ◽  
De Novo ◽  
Nuclear Accumulation ◽  
Tegument Protein ◽  
Bovine Herpesvirus 1 ◽  
Infected Cells ◽  
Herpesvirus 1

ABSTRACTTheUL47gene product, VP8, is the most abundant tegument protein of bovine herpesvirus 1 (BoHV-1). Previously, we demonstrated that aUL47-deleted BoHV-1 mutant (BoHV1-ΔUL47) exhibits 100-fold-reduced virulencein vitroand is avirulentin vivo. In this study, we demonstrated that VP8 expression or BoHV-1 infection inhibits interferon beta (IFN-β) signaling by using an IFN-α/β-responsive plasmid in a luciferase assay. As transducer and activator of transcription (STAT) is an essential component in the IFN-signaling pathways, the effect of VP8 on STAT was investigated. An interaction between VP8 and STAT1 was established by coimmunoprecipitation assays in both VP8-transfected and BoHV-1-infected cells. Two domains of VP8, amino acids 259 to 482 and 632 to 686, were found to be responsible for its interaction with STAT1. The expression of VP8 did not induce STAT1 ubiquitination or degradation. Moreover, VP8 did not reduce STAT1 tyrosine phosphorylation to downregulate IFN-β signaling. However, the expression of VP8 or a version of VP8 (amino acids 219 to 741) that contains the STAT1-interacting domains but not the nuclear localization signal prevented nuclear accumulation of STAT1. Inhibition of nuclear accumulation of STAT1 also occurred during BoHV-1 infection, while nuclear translocation of STAT1 was observed in BoHV1-ΔUL47-infected cells. During BoHV-1 infection, VP8 was detected in the cytoplasm at 2 h postinfection without anyde novoprotein synthesis, at which time STAT1 was already retained in the cytoplasm. These results suggest that viral VP8 downregulates IFN-β signaling early during infection, thus playing a role in overcoming the antiviral response of BoHV-1-infected cells.IMPORTANCESince VP8 is the most abundant protein in BoHV-1 virions and thus may be released in large amounts into the host cell immediately upon infection, we proposed that it might have a function in the establishment of conditions suitable for viral replication. Indeed, while nonessentialin vitro, it is critical for BoHV-1 replicationin vivo. In this study, we determined that VP8 plays a role in downregulation of the antiviral host response by inhibiting IFN-β signaling. VP8 interacted with and prevented nuclear accumulation of STAT1 at 2 h postinfection in the absence ofde novoviral protein synthesis. Two domains of VP8, amino acids 259 to 482 and 632 to 686, were found to be responsible for this interaction. These results provide a new functional role for VP8 in BoHV-1 infection and a potential explanation for the lack of viral replication of theUL47deletion mutant in cattle.

scholarly journals Cochaperone Interactions in Export of the Type III Needle Component PscF of Pseudomonas aeruginosa

2010 ◽  
Vol 192 (14) ◽  
pp. 3801-3808 ◽  
Author(s):  
Sophie Plé ◽  
Viviana Job ◽  
Andréa Dessen ◽  
Ina Attree
Keyword(s):  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Complex Formation ◽  
Hot Spot ◽  
Protein Stabilization ◽  
Site Directed Mutagenesis ◽  
Surface Stability ◽  
Type Iii

ABSTRACT Type III secretion (T3S) systems allow the export and translocation of bacterial effectors into the host cell cytoplasm. Secretion is accomplished by an 80-nm-long needle-like structure composed, in Pseudomonas aeruginosa, of the polymerized form of a 7-kDa protein, PscF. Two proteins, PscG and PscE, stabilize PscF within the bacterial cell before its export and polymerization. In this work we screened the 1,320-Å2 interface between the two chaperones, PscE and PscG, by site-directed mutagenesis and determined hot spot regions that are important for T3S function in vivo and complex formation in vitro. Three amino acids in PscE and five amino acids in PscG, found to be relevant for complex formation, map to the central part of the interacting surface. Stability assays on selected mutants performed both in vitro on purified PscE-PscG complexes and in vivo on P. aeruginosa revealed that PscE is a cochaperone that is essential for the stability of the main chaperone, PscG. Notably, when overexpressed from a bicistronic construct, PscG and PscF compensate for the absence of PscE in cytotoxic P. aeruginosa. These results show that all of the information needed for needle protein stabilization and folding, its presentation to the T3 secreton, and its export is present within the sequence of the PscG chaperone.

The 1- and 2-Naphthylalanine Analogs of Oxytocin and Vasopressin

1995 ◽  
Vol 60 (12) ◽  
pp. 2170-2177 ◽  
Author(s):  
Zdenko Procházka ◽  
Jiřina Slaninová
Keyword(s):  
Amino Acids ◽  
Solid Phase ◽  
Pressor Test

Solid phase technique on p-methylbenzhydrylamine resin was used for the synthesis of four analogs of oxytocin and four analogs of vasopressin with the non-coded amino acids L- or D- and 1- or 2-naphthylalanine and D-homoarginine. [L-1-Nal2]oxytocin, [D-1-Nal2]oxytocin, [L-2-Nal2]oxytocin, [D-2-Nal2]oxytocin, [L-1-Nal2, D-Har8]vasopressin, [D-1-Nal2, D-Har8]vasopressin, [L-2-Nal2, D-Har8]vasopressin and [D-2-Nal2, D-Har8]vasopressin were synthesized. All eight analogs were found to be uterotonic inhibitors in vitro and in vivo. Analogs with 2-naphthylalanine are stronger inhibitors, particularly in the vasopressin series than the analogs with 1-naphthylalanine. Analogs with 1-naphthylalanine have no activity in the pressor test, analogs with 2-naphthylalanine are weak pressor inhibitors.

Computational study for suppression of CD25/IL-2 interaction

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Moein Dehbashi ◽  
Zohreh Hojati ◽  
Majid Motovali-bashi ◽  
Mazdak Ganjalikhani-Hakemi ◽  
Akihiro Shimosaka ◽  
...  
Keyword(s):  
Small Molecules ◽  
Cancer Progression ◽  
Immune Escape ◽  
De Novo ◽  
Computational Study ◽  
Treg Cells ◽  
Homology Search ◽  
Small Interfering Rnas

AbstractCancer recurrence presents a huge challenge in cancer patient management. Immune escape is a key mechanism of cancer progression and metastatic dissemination. CD25 is expressed in regulatory T (Treg) cells including tumor-infiltrating Treg cells (TI-Tregs). These cells specially activate and reinforce immune escape mechanism of cancers. The suppression of CD25/IL-2 interaction would be useful against Treg cells activation and ultimately immune escape of cancer. Here, software, web servers and databases were used, at which in silico designed small interfering RNAs (siRNAs), de novo designed peptides and virtual screened small molecules against CD25 were introduced for the prospect of eliminating cancer immune escape and obtaining successful treatment. We obtained siRNAs with low off-target effects. Further, small molecules based on the binding homology search in ligand and receptor similarity were introduced. Finally, the critical amino acids on CD25 were targeted by a de novo designed peptide with disulfide bond. Hence we introduced computational-based antagonists to lay a foundation for further in vitro and in vivo studies.

scholarly journals Synthesis, Characterization and Evaluation of Peptide Nanostructures for Biomedical Applications

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4587
Author(s):  
Fanny d’Orlyé ◽  
Laura Trapiella-Alfonso ◽  
Camille Lescot ◽  
Marie Pinvidic ◽  
Bich-Thuy Doan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Biomedical Applications ◽  
Chemical Reactivity ◽  
Physical Stability ◽  
Chemical Properties ◽  
Building Blocks ◽  
Imaging Probes ◽  
Therapeutic Molecules

There is a challenging need for the development of new alternative nanostructures that can allow the coupling and/or encapsulation of therapeutic/diagnostic molecules while reducing their toxicity and improving their circulation and in-vivo targeting. Among the new materials using natural building blocks, peptides have attracted significant interest because of their simple structure, relative chemical and physical stability, diversity of sequences and forms, their easy functionalization with (bio)molecules and the possibility of synthesizing them in large quantities. A number of them have the ability to self-assemble into nanotubes, -spheres, -vesicles or -rods under mild conditions, which opens up new applications in biology and nanomedicine due to their intrinsic biocompatibility and biodegradability as well as their surface chemical reactivity via amino- and carboxyl groups. In order to obtain nanostructures suitable for biomedical applications, the structure, size, shape and surface chemistry of these nanoplatforms must be optimized. These properties depend directly on the nature and sequence of the amino acids that constitute them. It is therefore essential to control the order in which the amino acids are introduced during the synthesis of short peptide chains and to evaluate their in-vitro and in-vivo physico-chemical properties before testing them for biomedical applications. This review therefore focuses on the synthesis, functionalization and characterization of peptide sequences that can self-assemble to form nanostructures. The synthesis in batch or with new continuous flow and microflow techniques will be described and compared in terms of amino acids sequence, purification processes, functionalization or encapsulation of targeting ligands, imaging probes as well as therapeutic molecules. Their chemical and biological characterization will be presented to evaluate their purity, toxicity, biocompatibility and biodistribution, and some therapeutic properties in vitro and in vivo. Finally, their main applications in the biomedical field will be presented so as to highlight their importance and advantages over classical nanostructures.

scholarly journals EXTH-51. ANTI-INVASIVE EFFICACY AND SURVIVAL BENEFIT OF THE YAP-TEAD INHIBITOR VERTEPORFIN IN PRECLINICAL GLIOBLASTOMA MODELS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii98-ii98
Author(s):  
Anne Marie Barrette ◽  
Alexandros Bouras ◽  
German Nudelman ◽  
Zarmeen Mussa ◽  
Elena Zaslavsky ◽  
...  
Keyword(s):  
Survival Benefit ◽  
De Novo ◽  
Epithelial Mesenchymal Transition ◽  
Intraperitoneal Administration ◽  
Standard Of Care ◽  
Tumor Burden ◽  
Mesenchymal Transition ◽  
Protein Levels

Abstract Glioblastoma (GBM) remains an incurable disease, in large part due to its malignant infiltrative spread, and current clinical therapy fails to target the invasive nature of tumor cells in disease progression and recurrence. Here, we use the YAP-TEAD inhibitor Verteporfin to target a convergence point for regulating tumor invasion/metastasis and establish the robust anti-invasive therapeutic efficacy of this FDA-approved drug and its survival benefit across several preclinical glioma models. Using patient-derived GBM cells and orthotopic xenograft models (PDX), we show that Verteporfin treatment disrupts YAP/TAZ-TEAD activity and processes related to cell adhesion, migration and epithelial-mesenchymal transition. In-vitro, Verteporfin impairs tumor migration, invasion and motility dynamics. In-vivo, intraperitoneal administration of Verteporfin in mice with orthotopic PDX tumors shows consistent drug accumulation within the brain and decreased infiltrative tumor burden, across three independent experiments. Interestingly, PDX tumors with impaired invasion after Verteporfin treatment downregulate CDH2 and ITGB1 adhesion protein levels within the tumor microenvironment. Finally, Verteporfin treatment confers survival benefit in two independent PDX models: as monotherapy in de-novo GBM and in combination with standard-of-care chemoradiation in recurrent GBM. These findings indicate potential therapeutic value of this FDA-approved drug if repurposed for GBM patients.

Turnover of total proteins and ornithine aminotransferase during liver regeneration in rats

1980 ◽  
Vol 238 (1) ◽  
pp. E46-E52
Author(s):  
S. L. Augustine ◽  
R. W. Swick
Keyword(s):  
Amino Acids ◽  
Liver Regeneration ◽  
Protein Degradation ◽  
Partial Hepatectomy ◽  
Free Amino ◽  
Liver Protein ◽  
Ornithine Aminotransferase ◽  
Fractional Rate

The recovery of approximately 40% of the total liver protein during the first day after partial hepatectomy was shown to be due to the near cessation of protein breakdown rather than to an increase in protein synthesis. The decrease in degradation of total protein was less if rats were adrenalectomized or protein-depleted prior to partial hepatectomy. The effect of these treatments originally suggested that changes in free amino acid levels in liver might be related to the rate of protein degradation. However, no correlation was found between levels of total free amino acids and rates of breakdown. Measurements of individual amino acids during liver regeneration suggested that levels of free methionine and phenylalanine, amino acids that have been found to lower rates of protein degradation in vitro, are not correlated with rates of breakdown in vivo. The difference between the fractional rate of ornithine aminotransferase degradation (0.68/day and 0.28/day in sham-hepatectomized and partially hepatectomized rats, respectively) was sufficient to account for the higher level of this protein 3 days after surgery in the latter group.

scholarly journals PAICS contributes to gastric carcinogenesis and participates in DNA damage response by interacting with histone deacetylase 1/2

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Nan Huang ◽  
Chang Xu ◽  
Liang Deng ◽  
Xue Li ◽  
Zhixuan Bian ◽  
...  
Keyword(s):  
Dna Damage ◽  
Histone Deacetylase ◽  
Dna Damage Response ◽  
De Novo ◽  
Dna Damage Repair ◽  
Histone Deacetylase 1 ◽  
Damage Repair ◽  
Damage Response

AbstractPhosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.

Hippokampale Estrogensynthese und synaptische Plastizität

e-Neuroforum ◽  
2007 ◽  
Vol 13 (4) ◽  
Author(s):  
Lars Fester ◽  
Janine Prange-Kiel ◽  
Gabriele M. Rune
Keyword(s):  
De Novo ◽  
Synaptische Plastizität

ZusammenfassungUnsere Untersuchungen der letzten Jahre haben gezeigt, dass nicht das Ovar die Quelle für Estrogen induzierte synaptische Plastizität im Hippokampus ist, sondern dieses aus dem Hippokampus selber stammt und haben damit einen Paradigmawechsel eingeleitet, der Estrogen als Neuromodulator unabhängig vom Geschlecht identifiziert. Hippokampale Neurone von Ratten beiderlei Geschlechts sind in der Lage, aus Cholesterol Estrogene de novo zu synthetisieren. Diese hippokampale Estrogensynthese ist sowohl für den Erhalt von Spinesynapsen in vivo als auch in vitro essenziell. Die Hemmung der Estrogensynthese zieht einen Synapsenverlust nach sich und Langzeitpotenzierung ist nicht mehr induzierbar. Die Effekte von hippokampalem Estrogen sind auto-/parakriner Natur, die über die bekannten Estrogenrezeptor-Subtypen, ERα und ERβ, vermittelt werden. Die Regulation der hippokampalen Estrogensynthese erfolgt über GnRH und erklärt die Korrelation der Spinesynapsendichte mit dem weiblichen genitalen Zyklus, die für den Hippokampus spezifisch ist.

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