Dataset Information

N-acetyl ornithine deacetylase is a moonlighting protein and is involved in the adaptation of Entamoeba histolytica to nitrosative stress.

ABSTRACT: Adaptation of the Entamoeba histolytica parasite to toxic levels of nitric oxide (NO) that are produced by phagocytes may be essential for the establishment of chronic amebiasis and the parasite's survival in its host. In order to obtain insight into the mechanism of E. histolytica's adaptation to NO, E. histolytica trophozoites were progressively adapted to increasing concentrations of the NO donor drug, S-nitrosoglutathione (GSNO) up to a concentration of 110??M. The transcriptome of NO adapted trophozoites (NAT) was investigated by RNA sequencing (RNA-seq). N-acetyl ornithine deacetylase (NAOD) was among the 208 genes that were upregulated in NAT. NAOD catalyzes the deacetylation of N-acetyl-L-ornithine to yield ornithine and acetate. Here, we report that NAOD contributes to the better adaptation of the parasite to nitrosative stress (NS) and that this function does not depend on NAOD catalytic activity. We also demonstrated that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is detrimental to E. histolytica exposed to NS and that this detrimental effect is neutralized by NAOD or by a catalytically inactive NAOD (mNAOD). These results establish NAOD as a moonlighting protein, and highlight the unexpected role of this metabolic enzyme in the adaptation of the parasite to NS.

SUBMITTER: Shahi P

PROVIDER: S-EPMC5093748 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

N-acetyl ornithine deacetylase is a moonlighting protein and is involved in the adaptation of Entamoeba histolytica to nitrosative stress.

Shahi Preeti P Trebicz-Geffen Meirav M Nagaraja Shruti S Hertz Rivka R Baumel-Alterzon Sharon S Methling Karen K Lalk Michael M Mazumder Mohit M Samudrala Gourinath G Ankri Serge S

Scientific reports 20161103

Adaptation of the Entamoeba histolytica parasite to toxic levels of nitric oxide (NO) that are produced by phagocytes may be essential for the establishment of chronic amebiasis and the parasite's survival in its host. In order to obtain insight into the mechanism of E. histolytica's adaptation to NO, E. histolytica trophozoites were progressively adapted to increasing concentrations of the NO donor drug, S-nitrosoglutathione (GSNO) up to a concentration of 110 μM. The transcriptome of NO adapte ...[more]

PMID: 27808157

Similar Datasets

Project description:BACKGROUND: The polyamines putrescine, spermidine, and spermine are organic cations that are required for cell growth and differentiation. Ornithine decarboxylase (ODC), the first and rate-limiting enzyme in the polyamine biosynthetic pathway, is a highly regulated enzyme. METHODOLOGY AND RESULTS: To use this enzyme as a potential drug target, the gene encoding putative ornithine decarboxylase (ODC)-like sequence was cloned from Entamoeba histolytica, a protozoan parasite causing amoebiasis. DNA sequence analysis revealed an open reading frame (ORF) of approximately 1,242 bp encoding a putative protein of 413 amino acids with a calculated molecular mass of 46 kDa and a predicted isoelectric point of 5.61. The E. histolytica putative ODC-like sequence has 33% sequence identity with human ODC and 36% identity with the Datura stramonium ODC. The ORF is a single-copy gene located on a 1.9-Mb chromosome. The recombinant putative ODC protein (48 kDa) from E. histolytica was heterologously expressed in Escherichia coli. Antiserum against recombinant putative ODC protein detected a band of anticipated size approximately 46 kDa in E. histolytica whole-cell lysate. Difluoromethylornithine (DFMO), an enzyme-activated irreversible inhibitor of ODC, had no effect on the recombinant putative ODC from E. histolytica. Comparative modeling of the three-dimensional structure of E. histolytica putative ODC shows that the putative binding site for DFMO is disrupted by the substitution of three amino acids-aspartate-332, aspartate-361, and tyrosine-323-by histidine-296, phenylalanine-305, and asparagine-334, through which this inhibitor interacts with the protein. Amino acid changes in the pocket of the E. histolytica enzyme resulted in low substrate specificity for ornithine. It is possible that the enzyme has evolved a novel substrate specificity. CONCLUSION: To our knowledge this is the first report on the molecular characterization of putative ODC-like sequence from E. histolytica. Computer modeling revealed that three of the critical residues required for binding of DFMO to the ODC enzyme are substituted in E. histolytica, resulting in the likely loss of interactions between the enzyme and DFMO.

Project description:Entamoeba histolytica is an intestinal parasite infecting over 50 million people worldwide and is the causative agent of amebic dysentery and amoebic liver abscess. In the human host, E. histolytica experiences stress brought on by nutrient deprivation and the host immune response. To be a successful parasite, E. histolytica must counter the stress; therefore, understanding the stress response may uncover new drug targets. In many systems, the stress response includes down-regulation of protein translation, which is regulated by phosphorylation of eukaryotic initiation factor (eIF-2?). Previous work has demonstrated that phosphorylation of the E. histolytica eIF-2? (EheIF-2?) increases significantly when exposed to long-term serum starvation, oxidative stress, and long-term heat shock. However, the effects of reagents that are known to induce nitrosative or endoplasmic reticulum (ER) stresses, on EheIF-2? have yet to be evaluated. Nitrosative stress is part of the host's immune response and ER stress can be caused by several physiological or pathological factors. We treated E. histolytica cells with various reagents known to induce nitrosative stress (DPTA-NONOate and SNP) or ER stress (BFA and DTT). We examined the morphology of the ER, tracked phosphorylation of EheIF-2?, and assessed protein translation in control and stressed cells. While all four stress-inducing reagents caused a global reduction in protein translation, only DTT was capable of also inducing changes in the morphology of the ER (consistent with ER stress) and phosphorylation of EheIF-2?. This suggests that DTT authentically induces ER stress in E. histolytica and that this stress is managed by the eIF-2?-based system. This was supported by the observation that cells expressing a non-phosphorylatable version of eIF-2? were also highly sensitive to DTT-stress. Since protein translation decreased in the absence of phosphorylation of eIF-2? (after treatment with DPTA-NONOate, SNP or BFA), the data also indicate that there are alternative protein-translational control pathways in E. histolytica. Overall, our study further illuminates the stress response to nitrosative stress and ER stress in E. histolytica.

Project description:Entamoeba histolytica is a human pathogen, responsible for amoebic dysentery and invasive extraintestinal disease. The parasite faces several types of stress within the host, and to establish a successful infection it must generate a robust adaptive response against host defense mechanisms. In order to obtain comprehensive information of gene expression changes in E. histolytica under growth stress, we have (1) optimized the proteomics protocol to increase the protein coverage in E. histolytica, and (2) integrated proteomic data with transcriptomic analysis under the same conditions. We have applied this approach to better understand the cellular response during serum-starvation. Label-free quantitative proteomics was performed, and compared with mRNA levels based on RNA-seq data to decipher regulation at translational and transcriptional levels. Across all samples, 2344 proteins were identified, which is an improvement over the maximum recorded number in E. histolytica proteomic studies so far. A total of 127 proteins were found to be differentially expressed and associated with functions including antioxidant activity, cytoskeleton, translation, catalysis, and transport, which revealed proteomic signatures to distinguish serum-starved from normal trophozoites. Gal/GalNAc-inhibitable lectin, Lgls, Hgl3 and Igl were repeatedly identified as significantly altered in serum-stress condition. Further, integration of transcriptomic and proteomic data revealed instances of post-transcriptional regulation. Six highly expressed transcripts had low corresponding protein expression, indicating translational repression. Conversely, eleven transcripts showed much greater downregulation compared with their corresponding proteins, indicating translational induction, or increased stability of these proteins during serum stress in E. histolytica. This multi-omics approach enables more refined gene expression analysis that would not be possible at the mRNA or protein levels alone. Our study provides important data to further understand the adaptive response of E. histolytica to growth stress.

Dataset Information

N-acetyl ornithine deacetylase is a moonlighting protein and is involved in the adaptation of Entamoeba histolytica to nitrosative stress.

Publications

N-acetyl ornithine deacetylase is a moonlighting protein and is involved in the adaptation of Entamoeba histolytica to nitrosative stress.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets