scholarly journals The Helicobacter pylori HspR-Modulator CbpA Is a Multifunctional Heat-Shock Protein

2020 ◽  
Vol 8 (2) ◽  
pp. 251
Author(s):  
Simona Pepe ◽  
Vincenzo Scarlato ◽  
Davide Roncarati
Keyword(s):  
Helicobacter Pylori ◽  
Heat Shock ◽  
Functional Characterization ◽  
Direct Interaction ◽  
Binding Activity ◽  
Regulatory Role ◽  
Heat Shock Gene ◽  
Dna Binding Activity ◽  
H Pylori

The medically important human pathogen Helicobacter pylori relies on a collection of highly conserved heat-shock and chaperone proteins to preserve the integrity of cellular polypeptides and to control their homeostasis in response to external stress and changing environmental conditions. Among this set of chaperones, the CbpA protein has been shown to play a regulatory role in heat-shock gene regulation by directly interacting with the master stress-responsive repressor HspR. Apart from this regulatory role, little is known so far about CbpA functional activities. Using biochemistry and molecular biology approaches, we have started the in vitro functional characterization of H. pylori CbpA. Specifically, we show that CbpA is a multifunctional protein, being able to bind DNA and to stimulate the ATPase activity of the major chaperone DnaK. In addition, we report a preliminary observation suggesting that CbpA DNA-binding activity can be affected by the direct interaction with the heat-shock master repressor HspR, supporting the hypothesis of a reciprocal crosstalk between these two proteins. Thus, our work defines novel functions for H. pylori CbpA and stimulates further studies aimed at the comprehension of the complex regulatory interplay among chaperones and heat-shock transcriptional regulators.

scholarly journals Repurposing Dihydropyridines for Treatment of Helicobacter pylori Infection

Pharmaceutics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 681 ◽  
Author(s):  
Andrés González ◽  
Javier Casado ◽  
Eduardo Chueca ◽  
Sandra Salillas ◽  
Adrián Velázquez-Campoy ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antimicrobial Agents ◽  
Antihypertensive Drugs ◽  
Response Regulator ◽  
Antimicrobial Activities ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
H Pylori

Antibiotic resistance is a major cause of the increasing failures in the current eradication therapies against Helicobacter pylori. In this scenario, repurposing drugs could be a valuable strategy to fast-track novel antimicrobial agents. In the present study, we analyzed the inhibitory capability of 1,4-dihydropyridine (DHP) antihypertensive drugs on the essential function of the H. pylori response regulator HsrA and investigated both the in vitro antimicrobial activities and the in vivo efficacy of DHP treatments against H. pylori. Six different commercially available and highly prescribed DHP drugs—namely, Nifedipine, Nicardipine, Nisoldipine, Nimodipine, Nitrendipine, and Lercanidipine—noticeably inhibited the DNA binding activity of HsrA and exhibited potent bactericidal activities against both metronidazole- and clarithromycin-resistant strains of H. pylori, with minimal inhibitory concentration (MIC) values in the range of 4 to 32 mg/L. The dynamics of the decline in the bacterial counts at 2 × MIC appeared to be correlated with the lipophilicity of the drugs, suggesting different translocation efficiencies of DHPs across the bacterial membrane. Oral treatments with 100 mg/kg/day of marketed formulations of Nimodipine or Nitrendipine in combination with omeprazole significantly reduced the H. pylori gastric colonization in mice. The results presented here support a novel therapeutic solution for treatment of antibiotic-resistant H. pylori infections.

Activation of heat shock factor 2 during hemin-induced differentiation of human erythroleukemia cells

1992 ◽  
Vol 12 (9) ◽  
pp. 4104-4111
Author(s):  
L Sistonen ◽  
K D Sarge ◽  
B Phillips ◽  
K Abravaya ◽  
R I Morimoto
Keyword(s):  
Heat Shock ◽  
Dna Binding ◽  
Binding Activity ◽  
Erythroid Cell ◽  
Hsp70 Gene ◽  
Mobility Shift ◽  
Heat Shock Element ◽  
Dna Binding Activity ◽  
Erythroleukemia Cells

Hemin induces nonterminal differentiation of human K562 erythroleukemia cells, which is accompanied by the expression of certain erythroid cell-specific genes, such as the embryonic and fetal globins, and elevated expression of the stress genes hsp70, hsp90, and grp78/BiP. Previous studies revealed that, as during heat shock, transcriptional induction of hsp70 in hemin-treated cells is mediated by activation of heat shock transcription factor (HSF), which binds to the heat shock element (HSE). We report here that hemin activates the DNA-binding activity of HSF2, whereas heat shock induces predominantly the DNA-binding activity of a distinct factor, HSF1. This constitutes the first example of HSF2 activation in vivo. Both hemin and heat shock treatments resulted in equivalent levels of HSF-HSE complexes as analyzed in vitro by gel mobility shift assay, yet transcription of the hsp70 gene was stimulated much less by hemin-induced HSF than by heat shock-induced HSF. Genomic footprinting experiments revealed that hemin-induced HSF and heat shock-induced HSF, HSF2, and HSF1, respectively, occupy the HSE of the human hsp70 promoter in a similar yet not identical manner. We speculate that the difference in occupancy and/or in the transcriptional abilities of HSF1 and HSF2 accounts for the observed differences in the stimulation of hsp70 gene transcription.

scholarly journals Dual Control of Helicobacter pylori Heat Shock Gene Transcription by HspR and HrcA

2004 ◽  
Vol 186 (10) ◽  
pp. 2956-2965 ◽  
Author(s):  
Gunther Spohn ◽  
Alberto Danielli ◽  
Davide Roncarati ◽  
Isabel Delany ◽  
Rino Rappuoli ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Heat Shock ◽  
Heat Shock Gene ◽  
Inverted Repeats ◽  
Dual Control ◽  
Shock Gene ◽  
Heat Shock Gene Expression ◽  
H Pylori

ABSTRACT The HspR repressor regulates transcription of the groESL, hrcA-grpE-dnaK, and cbpA-hspR-orf operons of Helicobacter pylori. Here we show that two of the HspR-regulated operons, namely, the groESL and dnaK operons, encoding the major cellular chaperone machineries are also regulated by the H. pylori homologue of the HrcA repressor. Similarly to the hspR mutation, deletion of the hrcA gene also leads to complete derepression of the P gro and P hrc promoters. The presence of both HspR and HrcA is therefore necessary for regulated transcription from these promoters. HrcA binds directly to P gro and P hrc , likely contacting two inverted repeats with similarity to the CIRCE motif, which are present on both promoters. HrcA regulation is, however, shown to depend on binding of the HspR protein, since deletion of the HspR-binding site of the P gro promoter leads to loss of heat inducibility of this promoter. In contrast, transcription from the P cbp promoter is regulated solely by HspR. HspR is also shown to form oligomers in vivo through a stretch of hydrophobic repeats between amino acid positions 66 and 97. The implications of these findings for the elucidation of the networks regulating heat shock gene expression in H. pylori are discussed.

Helicobacter pylori helicase loader protein Hp0897 shows unique functions of N- and C-terminal regions

2019 ◽  
Vol 476 (21) ◽  
pp. 3261-3279
Author(s):  
Ajay Kumar ◽  
Abhik Saha ◽  
Vijay K. Verma ◽  
Suman Kumar Dhar
Keyword(s):  
Helicobacter Pylori ◽  
Cell Elongation ◽  
Function Analysis ◽  
Binding Activity ◽  
Full Length ◽  
Cell Phenotype ◽  
Dna Binding Activity ◽  
H Pylori

Helicase loaders are required for the loading of helicases at the vicinity of replication origins. In Helicobacter pylori, Hp0897 has been shown to be a potential helicase loader for replicative helicase (HpDnaB) although it does not show any sequence homology with conventional DnaC like helicase loader proteins. Therefore, it is important to investigate the in vivo role of Hp0897 and structure-function analysis with respect to domain mapping of Hp0897 and HpDnaB. Although HporiC is divided into oriC1 and oriC2, the latter has been assigned as functional origin based on loading of initiator protein HpDnaA. Using chromatin immunoprecipitation (ChIP) experiment, we show preferential binding of Hp0897 at oriC2 over oriC1 like HpDnaA highlighting its helicase loader function in vivo. Furthermore, we generated series of deletion mutants for HpDnaB and Hp0897 that enabled us to map the domains of interaction between these two proteins. Interestingly, the C-terminal domain of Hp0897 (Hp0897CTD) shows stronger interaction with HpDnaB over the N-terminal region of Hp0897 (Hp0897NTD). Similar to the full-length protein, Hp0897CTD also stimulates the DNA binding activity of HpDnaB. Furthermore, overexpression of Hp0897 full-length protein in H. pylori leads to an elongated cell phenotype. While the overexpression of Hp0897CTD does not show a phenotype of cell elongation, overexpression of Hp0897NTD shows extensive cell elongation. These results highlight the possible role of Hp0897CTD in helicase loading and Hp0897NTD's unique function linked to cell division that make Hp0897 as a potential drug target against H. pylori.

HDAC1 Can Deacetylate GATA-1 and Regulates Its Activity through a FOG-1 Independent Manner

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5125-5125
Author(s):  
Bowen Yan ◽  
Tao Yang ◽  
Suming Huang ◽  
Yi Qiu
Keyword(s):  
Conflicts Of Interest ◽  
Direct Interaction ◽  
Binding Activity ◽  
Wild Type ◽  
Independent Manner ◽  
Erythroid Progenitor ◽  
Histone Deacetylase 1 ◽  
Dna Binding Activity ◽  
A Genome

Abstract The transcription factor GATA-1 is essential for erythroid and megakaryocytic cell differentiation and maturation. It has been well documented that GATA-1 can indirectly interact with histone deacetylase 1 (HDAC1) containing NuRD corepressor complexes through an association with FOG-1. Our previous work also shows that HDAC1 acetylation modulates the activity of FOG-1 associated NuRD complexes. Earlier studies show GATA-1 can be acetylated by p300/CBP, and the acetylation modulates GATA-1 binding activity to chromatin. However, it is not clear whether the acetylation can be reversed by a deacetylase. In this study, we found that GATA-1 can directly interact with HDAC1 in a FOG-1 independent manner. The interaction results in the deacetylation of GATA-1. We have identified two arginine sites within GATA-1 that are important for its interaction with HDAC1. The arginine to alanine mutation on these sites (2RA) can largely decrease the interaction of these two proteins, but doesn't affect its interaction with FOG-1, indicating that the direct interactions with HDAC1 and FOG-1 dependent association of NuRD complexes are separate events. The mutations also do not affect GATA-1 DNA binding activity in vitro. To further investigate the function of this interaction in erythropoiesis, we introduced wild type or the 2RA mutant of GATA-1 fused with estrogen receptor ligand binding domains into G1E cells, a GATA-1-null erythroid progenitor cell line. Upon estradiol induction, GATA-1 2RA inhibits the differentiation in G1E cells. We performed RNA sequencing to study the effect of GATA-1 2RA in gene expression in comparison with wild type GATA-1 and GATA-1-V205M (a mutation abolished binding with FOG-1) on a genome wild scale. GATA-1 2RA affects GATA-1 function in both GATA-1 activated and repressed genes. Although there is some overlap between 2RA and V205M mutations in both activated and repressed genes, more genes affected by these two mutations are different. Thus, this study unveils a novel regulation for GATA-1 by its direct interaction with HDAC1 during hematopoiesis. Disclosures No relevant conflicts of interest to declare.

scholarly journals Activation of heat shock factor 2 during hemin-induced differentiation of human erythroleukemia cells.

1992 ◽  
Vol 12 (9) ◽  
pp. 4104-4111 ◽  
Author(s):  
L Sistonen ◽  
K D Sarge ◽  
B Phillips ◽  
K Abravaya ◽  
R I Morimoto
Keyword(s):  
Heat Shock ◽  
Dna Binding ◽  
Binding Activity ◽  
Erythroid Cell ◽  
Hsp70 Gene ◽  
Mobility Shift ◽  
Heat Shock Element ◽  
Dna Binding Activity ◽  
Erythroleukemia Cells

Hemin induces nonterminal differentiation of human K562 erythroleukemia cells, which is accompanied by the expression of certain erythroid cell-specific genes, such as the embryonic and fetal globins, and elevated expression of the stress genes hsp70, hsp90, and grp78/BiP. Previous studies revealed that, as during heat shock, transcriptional induction of hsp70 in hemin-treated cells is mediated by activation of heat shock transcription factor (HSF), which binds to the heat shock element (HSE). We report here that hemin activates the DNA-binding activity of HSF2, whereas heat shock induces predominantly the DNA-binding activity of a distinct factor, HSF1. This constitutes the first example of HSF2 activation in vivo. Both hemin and heat shock treatments resulted in equivalent levels of HSF-HSE complexes as analyzed in vitro by gel mobility shift assay, yet transcription of the hsp70 gene was stimulated much less by hemin-induced HSF than by heat shock-induced HSF. Genomic footprinting experiments revealed that hemin-induced HSF and heat shock-induced HSF, HSF2, and HSF1, respectively, occupy the HSE of the human hsp70 promoter in a similar yet not identical manner. We speculate that the difference in occupancy and/or in the transcriptional abilities of HSF1 and HSF2 accounts for the observed differences in the stimulation of hsp70 gene transcription.

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