scholarly journals A mutagenesis screen for essential plastid biogenesis genes in human malaria parasites

2018 ◽  
Author(s):  
Yong Tang ◽  
Thomas R. Meister ◽  
Marta Walczak ◽  
Michael J. Pulkoski-Gross ◽  
Sanjay B. Hari ◽  
...  
Keyword(s):  
Drug Targets ◽  
Metabolic Enzyme ◽  
Parasitic Diseases ◽  
Organelle Biogenesis ◽  
Cellular Functions ◽  
Fluorescent Reporter ◽  
Forward Genetic Screen ◽  
Mutagenesis Screen ◽  
Eukaryotic Diversity ◽  
Tim Barrel

SummaryEndosymbiosis has driven major molecular and cellular innovations. Plasmodium spp. parasites that cause malaria contain an essential, non-photosynthetic plastid, the apicoplast, which originated from a secondary (eukaryote-eukaryote) endosymbiosis. To discover organellar pathways with evolutionary and biomedical significance, we performed a mutagenesis screen for essential genes required for apicoplast biogenesis in P. falciparum. Apicoplast-minus mutants were isolated using a chemical rescue that permits conditional disruption of the apicoplast and a new fluorescent reporter for organelle loss. Five candidate genes were validated (out of 12 identified), including a TIM-barrel protein that likely derived from a core metabolic enzyme but evolved a new activity. Our results demonstrate the first forward genetic screen to assign essential cellular functions to unannotated P. falciparum genes. A putative TIM-barrel enzyme and other newly-identified apicoplast biogenesis proteins open opportunities to discover new mechanisms of organelle biogenesis, molecular evolution underlying eukaryotic diversity, and drug targets against multiple parasitic diseases.

scholarly journals Histone Deacetylase Enzymes as Potential Drug Targets in Cancer and Parasitic Diseases

2006 ◽  
Vol 2006 ◽  
pp. 1-10 ◽  
Author(s):  
Mehdi Ouaissi ◽  
Ali Ouaissi
Keyword(s):  
Transcriptional Activation ◽  
Histone Deacetylases ◽  
Drug Targets ◽  
Large Family ◽  
Current Data ◽  
Functional Study ◽  
Parasitic Diseases ◽  
Antitumor Effects ◽  
Protozoan Infections

The elucidation of the mechanisms of transcriptional activation and repression in eukaryotic cells has shed light on the important role of acetylation-deacetylation of histones mediated by histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively. Another group belonging to the large family of sirtuins (silent information regulators (SIRs)) has an (nicotinamide adenine dinucleotide)NAD+-dependent HDAC activity. Several inhibitors of HDACs (HDIs) have been shown to exert antitumor effects. Interestingly, some of the HDIs exerted a broad spectrum of antiprotozoal activity. The purpose of this review is to analyze some of the current data related to the deacetylase enzymes as a possible target for drug development in cancer and parasitic diseases with special reference to protozoan infections. Given the structural differences among members of this family of enzymes, development of specific inhibitors will not only allow selective therapeutic intervention, but may also provide a powerful tool for functional study of these enzymes.

scholarly journals Visualizing the dynamics of exported bacterial proteins with the chemogenetic fluorescent reporter FAST

2020 ◽  
Author(s):  
Yankel Chekli ◽  
Caroline Peron-Cane ◽  
Dario Dell’Arciprete ◽  
Jean-François Allemand ◽  
Chenge Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Cell Surface ◽  
Bacterial Cell ◽  
Surface Proteins ◽  
Cellular Functions ◽  
Reporter Protein ◽  
Cell Surface Proteins ◽  
Fluorescent Reporter ◽  
Bacterial Proteins

AbstractBacterial proteins exported to the cell surface play key cellular functions. However, despite the interest to study the localization of surface proteins such as adhesins, transporters or hydrolases, monitoring their dynamics in live imaging remains challenging, due to the limited availability of fluorescent probes remaining functional after secretion. In this work, we used the Escherichia coli intimin and the Listeria monocytogenes InlB invasin as surface exposed scaffolds fused with the recently developed chemogenetic fluorescent reporter protein FAST. Using both membrane permeant (HBR-3,5DM) and non-permeant (HBRAA-3E) fluorogens that fluoresce upon binding to FAST, we demonstrated that fully functional FAST can be exposed at the cell surface and specifically tagged on the external side of the bacterial envelop in both diderm and monoderm bacteria. Our work opens new avenues to study of the organization and dynamics of the bacterial cell surface proteins.

scholarly journals A Human DUB Protein Array for Clarification of Linkage Specificity of Polyubiquitin Chain and Application to Evaluation of Its Inhibitors

Biomedicines ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 152
Author(s):  
Hirotaka Takahashi ◽  
Satoshi Yamanaka ◽  
Shohei Kuwada ◽  
Kana Higaki ◽  
Kohki Kido ◽  
...  
Keyword(s):  
Drug Targets ◽  
Protein Array ◽  
Polyubiquitin Chain ◽  
Deubiquitinating Enzymes ◽  
Cellular Functions ◽  
Cellular Processes ◽  
Model Study ◽  
Biochemical Analyses ◽  
Almost All

Protein ubiquitinations play pivotal roles in many cellular processes, including homeostasis, responses to various stimulations, and progression of diseases. Deubiquitinating enzymes (DUBs) remove ubiquitin molecules from ubiquitinated proteins and cleave the polyubiquitin chain, thus negatively regulating numerous ubiquitin-dependent processes. Dysfunctions of many DUBs reportedly cause various diseases; therefore, DUBs are considered as important drug targets, although the biochemical characteristics and cellular functions of many DUBs are still unclear. Here, we established a human DUB protein array to detect the activity and linkage specificity of almost all human DUBs. Using a wheat cell-free protein synthesis system, 88 full-length recombinant human DUB proteins were prepared and termed the DUB array. In vitro DUB assays were performed with all of these recombinant DUBs, using eight linkage types of diubiquitins as substrates. As a result, 80 DUBs in the array showed DUB activities, and their linkage specificities were determined. These 80 DUBs included many biochemically uncharacterized DUBs in the past. In addition, taking advantage of these active DUB proteins, we applied the DUB array to evaluate the selectivities of DUB inhibitors. We successfully developed a high-throughput and semi-quantitative DUB assay based on AlphaScreen technology, and a model study using two commercially available DUB inhibitors revealed individual selectivities to 29 DUBs, as previously reported. In conclusion, the DUB array established here is a powerful tool for biochemical analyses and drug discovery for human DUBs.

scholarly journals Molybdenum Enzymes and How They Support Virulence in Pathogenic Bacteria

2020 ◽  
Vol 11 ◽  
Author(s):  
Qifeng Zhong ◽  
Bostjan Kobe ◽  
Ulrike Kappler
Keyword(s):  
Drug Targets ◽  
Pathogenic Bacteria ◽  
Bacterial Pathogens ◽  
Energy Generation ◽  
Cellular Functions ◽  
Pathogen Fitness ◽  
Future Drug ◽  
Domains Of Life ◽  
Cofactor Biosynthesis ◽  
And Function

Mononuclear molybdoenzymes are highly versatile catalysts that occur in organisms in all domains of life, where they mediate essential cellular functions such as energy generation and detoxification reactions. Molybdoenzymes are particularly abundant in bacteria, where over 50 distinct types of enzymes have been identified to date. In bacterial pathogens, all aspects of molybdoenzyme biology such as molybdate uptake, cofactor biosynthesis, and function of the enzymes themselves, have been shown to affect fitness in the host as well as virulence. Although current studies are mostly focused on a few key pathogens such as Escherichia coli, Salmonella enterica, Campylobacter jejuni, and Mycobacterium tuberculosis, some common themes for the function and adaptation of the molybdoenzymes to pathogen environmental niches are emerging. Firstly, for many of these enzymes, their role is in supporting bacterial energy generation; and the corresponding pathogen fitness and virulence defects appear to arise from a suboptimally poised metabolic network. Secondly, all substrates converted by virulence-relevant bacterial Mo enzymes belong to classes known to be generated in the host either during inflammation or as part of the host signaling network, with some enzyme groups showing adaptation to the increased conversion of such substrates. Lastly, a specific adaptation to bacterial in-host survival is an emerging link between the regulation of molybdoenzyme expression in bacterial pathogens and the presence of immune system-generated reactive oxygen species. The prevalence of molybdoenzymes in key bacterial pathogens including ESKAPE pathogens, paired with the mounting evidence of their central roles in bacterial fitness during infection, suggest that they could be important future drug targets.

scholarly journals ClpX is Essential and Activated by Single Strand DNA Binding Protein in Mycobacteria

2020 ◽  
Author(s):  
Jemila C. Kester ◽  
Olga Kandror ◽  
Tatos Akopian ◽  
Michael R. Chase ◽  
Junhao Zhu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Replication ◽  
Dna Binding ◽  
Drug Targets ◽  
Atp Hydrolysis ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Cellular Functions ◽  
Mycobacterial Growth ◽  
Dna Maintenance

The ClpP1P2 proteolytic complex is essential in Mycobacterium tuberculosis (Mtb). Proteolysis by ClpP1P2 requires an associated ATPase, either ClpX or ClpC1. Here, we seek to define the unique contributions of the ClpX ATPase to mycobacterial growth. We formally demonstrate that ClpX is essential for mycobacterial growth and to understand its essential functions, we identify ClpX-His-interacting proteins by pulldown and tandem mass spectrometry. We find an unexpected association between ClpX and proteins involved in DNA replication, and confirm a physical association between ClpX and the essential DNA maintenance protein Single-Stranded DNA Binding protein (SSB). Purified SSB is not degraded by ClpXP1P2; instead SSB enhances ATP hydrolysis by ClpX and degradation of the model substrate GFP-SsrA by ClpXP1P2. This activation of ClpX is mediated by the C-terminal tail of SSB that had been implicated in the activation of other ATPases associated with DNA replication. Consistent with the predicted interactions, depletion of clpX transcript perturbs DNA replication. These data reveal that ClpX participates in DNA replication and identify the first activator of ClpX in mycobacteria. IMPORTANCE Tuberculosis, caused by Mycobacterium tuberculosis, imposes a major global health burden, surpassing HIV and malaria in annual deaths. The ClpP1P2 proteolytic complex and its cofactor ClpX are attractive drug targets, but their precise cellular functions are unclear. This work confirms ClpX’s essentiality and describes a novel interaction between ClpX and SSB, a component of the DNA replication machinery. Further, we demonstrate that a loss of ClpX is sufficient to interrupt DNA replication, suggesting the ClpX-SSB complex may play a role in DNA replication in mycobacteria.

scholarly journals Circadian Regulation of Diverse Gene Products Revealed by mRNA Expression Profiling of Synchronized Fibroblasts

2001 ◽  
Vol 276 (50) ◽  
pp. 46751-46758 ◽  
Author(s):  
Christophe Grundschober ◽  
Franck Delaunay ◽  
Anja Pühlhofer ◽  
Gerard Triqueneaux ◽  
Vincent Laudet ◽  
...  
Keyword(s):  
Drug Targets ◽  
Expression Patterns ◽  
Gene Products ◽  
Cellular Functions ◽  
Total Period ◽  
Circadian Genes ◽  
Mrna Profiling ◽  
Circadian Expression ◽  
Rat Fibroblasts ◽  
Mrna Expression Profiling

Genes under a 24-h regulation period may represent drug targets relevant to diseases involving circadian dysfunctions. As a testing model of the circadian clock system, we have used synchronized rat fibroblasts that are known to express at least six genes in a circadian fashion. We have determined the expression patterns of 9957 transcripts every 4 h over a total period of 76 h using high density oligonucleotide microarrays. The spectral analysis of our mRNA profiling data indicated that ∼2% (85 genes) of all expressed genes followed a robust circadian pattern. We have confirmed the circadian expression of previously known clock or clock-driven genes, and we identified 81 novel circadian genes. The majority of the circadian-regulated gene products are known and are involved in diverse cellular functions. We have classified these circadian genes in seven clusters according to their phase of cycling. Our pathway analysis of the mRNA profiling data strongly suggests a direct link between circadian rhythm and cell cycle.

scholarly journals Unbiased Identification of Extracellular Protein–Protein Interactions for Drug Target and Biologic Drug Discovery

2021 ◽  
Author(s):  
Shengya Cao ◽  
Nadia Martinez-Martin
Keyword(s):  
Drug Discovery ◽  
Protein Interactions ◽  
Drug Target ◽  
Drug Targets ◽  
Extracellular Protein ◽  
Protein Protein Interactions ◽  
Cellular Functions ◽  
Drug Target Discovery ◽  
Technological Improvements ◽  
Targeted Drug Discovery

Technological improvements in unbiased screening have accelerated drug target discovery. In particular, membrane-embedded and secreted proteins have gained attention because of their ability to orchestrate intercellular communication. Dysregulation of their extracellular protein–protein interactions (ePPIs) underlies the initiation and progression of many human diseases. Practically, ePPIs are also accessible for modulation by therapeutics since they operate outside of the plasma membrane. Therefore, it is unsurprising that while these proteins make up about 30% of human genes, they encompass the majority of drug targets approved by the FDA. Even so, most secreted and membrane proteins remain uncharacterized in terms of binding partners and cellular functions. To address this, a number of approaches have been developed to overcome challenges associated with membrane protein biology and ePPI discovery. This chapter will cover recent advances that use high-throughput methods to move towards the generation of a comprehensive network of ePPIs in humans for future targeted drug discovery.

scholarly journals In silicoidentification of metabolic enzyme drug targets inBurkholderia pseudomallei

2015 ◽  
Author(s):  
Jean F. Challacombe
Keyword(s):  
In Silico ◽  
Drug Targets ◽  
Culture Media ◽  
Metabolic Modeling ◽  
Host Cells ◽  
Natural Resistance ◽  
Metabolic Enzyme ◽  
Chronic Infections ◽  
Genome Scale ◽  
Nutrient Conditions

AbstractThe intracellular pathogenBurkholderia pseudomallei,which is endemic to parts of southeast Asia and northern Australia, causes the disease melioidosis. Although acute infections can be treated with antibiotics, melioidosis is difficult to cure, and some patients develop chronic infections or a recrudescence of the disease months or years after treatment of the initial infection.B. pseudomalleistrains have a high level of natural resistance to a variety of antibiotics, and with limited options for new antibiotics on the horizon, new alternatives are needed. The aim of the present study was to characterize the metabolic capabilities ofB. pseudomallei, identify metabolites crucial for pathogen survival, understand the metabolic interactions that occur between pathogen and host cells, and determine if metabolic enzymes produced by the pathogen might be potential antibacterial targets. This aim was accomplished through genome scale metabolic modeling under different external conditions: 1) including all nutrients that could be consumed by the model, and 2) providing only the nutrients available in culture media. Using this approach, candidate chokepoint enzymes were identified, then knocked outin silicounder the different nutrient conditions. The effect of each knockout on the metabolic network was examined. When five of the candidate chokepoints were knocked outin silico, the flux through theB. pseudomalleinetwork was decreased, depending on the nutrient conditions. These results demonstrate the utility of genome-scale metabolic modeling methods for drug target identification inB. pseudomallei.

scholarly journals Involvement of IL-13 and Tissue Transglutaminase in Liver Granuloma and Fibrosis afterSchistosoma japonicumInfection

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Juanjuan Tang ◽  
Huayi Huang ◽  
Xiaofang Ji ◽  
Xunmin Zhu ◽  
Yinyan Li ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Drug Targets ◽  
Tissue Transglutaminase ◽  
Parasitic Diseases ◽  
Central Function ◽  
Liver Fibrogenesis ◽  
Multifunctional Enzymes ◽  
The Relationship ◽  
Potential Drug Targets ◽  
Liver Granuloma

Schistosomiasis, one of the most devastating parasitic diseases, is caused bySchistosoma japonicum(Sj) infection resulting in serious liver fibrosis. Interleukin- (IL-) 13, which is produced byTH2  cells, is a critical profibrotic cytokine found in various organs, including the liver. Tissue transglutaminase (tTG), a group of multifunctional enzymes, serves a central function in the pathogenesis of chronic liver diseases. However, the relationship between IL-13, tTG, and liver fibrosis duringSchistosomainfection has not been established. This study investigated the involvement of IL-13 and tTG in liver fibrogenesis duringSjinfection in mice. Five weeks afterSjinfection, granuloma and fibrosis development in the liver coincided with an increase in IL-13 and tTG in the liver and the upregulation of serum IL-13 in infected mice. Administration of cystamine, an inhibitor of tTG, abrogated the increase in both tTG and IL-13 in infected mice and ameliorated liver fibrogenesis and granuloma development. This result establishes a novel link among IL-13, tTG, and liver granuloma and fibrosis underSjinfection. Based on their important functions in liver fibrosis induced bySjinfection, IL-13 and tTG could be promising potential drug targets against schistosomiasis.

scholarly journals Target-Directed Approaches for Screening Small Molecules against RNA Targets

2020 ◽  
Vol 25 (8) ◽  
pp. 869-894 ◽  
Author(s):  
Hafeez S. Haniff ◽  
Laurent Knerr ◽  
Jonathan L. Chen ◽  
Matthew D. Disney ◽  
Helen L. Lightfoot
Keyword(s):  
Small Molecules ◽  
Small Molecule ◽  
Drug Targets ◽  
Industrial Development ◽  
Rna Binding ◽  
Cellular Functions ◽  
Rna Molecules ◽  
The Face ◽  
Rna Binders ◽  
The Right

RNA molecules have a variety of cellular functions that can drive disease pathologies. They are without a doubt one of the most intriguing yet controversial small-molecule drug targets. The ability to widely target RNA with small molecules could be revolutionary, once the right tools, assays, and targets are selected, thereby defining which biomolecules are targetable and what constitutes drug-like small molecules. Indeed, approaches developed over the past 5–10 years have changed the face of small molecule–RNA targeting by addressing historic concerns regarding affinity, selectivity, and structural dynamics. Presently, selective RNA–protein complex stabilizing drugs such as branaplam and risdiplam are in clinical trials for the modulation of SMN2 splicing, compounds identified from phenotypic screens with serendipitous outcomes. Fully developing RNA as a druggable target will require a target engagement-driven approach, and evolving chemical collections will be important for the industrial development of this class of target. In this review we discuss target-directed approaches that can be used to identify RNA-binding compounds and the chemical knowledge we have today of small-molecule RNA binders.

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