scholarly journals Cellular Effects of 2´,3´-Cyclic Nucleotide Monophosphates in Gram-Negative Bacteria

2021 ◽  
Author(s):  
Yashasvika Duggal ◽  
Jennifer E. Kurasz ◽  
Benjamin M. Fontaine ◽  
Nick J. Marotta ◽  
Shikha S. Chauhan ◽  
...  
Keyword(s):  
Cyclic Nucleotide ◽  
Intracellular Signaling ◽  
Biofilm Formation ◽  
Second Messengers ◽  
Rna Degradation ◽  
Signaling Molecules ◽  
Nucleotide Metabolism ◽  
E Coli ◽  
Cellular Processes ◽  
Intracellular Signaling Molecules

Organismal adaptations to environmental stimuli are governed by intracellular signaling molecules such as nucleotide second messengers. Recent studies have identified functional roles for the non-canonical 2´,3´-cyclic nucleotide monophosphates (2´,3´-cNMPs) in both eukaryotes and prokaryotes. In Escherichia coli , 2´,3´-cNMPs are produced by RNase I-catalyzed RNA degradation, and these cyclic nucleotides modulate biofilm formation through unknown mechanisms. The present work dissects cellular processes in E. coli and Salmonella Typhimurium that are modulated by 2´,3´-cNMPs through the development of cell-permeable 2´,3´-cNMP analogs and a 2´,3´-cyclic nucleotide phosphodiesterase. Utilization of these chemical and enzymatic tools, in conjunction with phenotypic and transcriptomic investigations, identified pathways regulated by 2´,3´-cNMPs, including flagellar motility and biofilm formation, and by oligoribonucleotides with 3’-terminal 2´,3´-cyclic phosphates, including responses to cellular stress. Furthermore, interrogation of metabolomic and organismal databases has identified 2´,3´-cNMPs in numerous organisms and homologs of the E. coli metabolic proteins that are involved in key eukaryotic pathways. Thus, the present work provides key insights into the roles of these understudied facets of nucleotide metabolism and signaling in prokaryotic physiology and suggest broad roles for 2´,3´-cNMPs among bacteria and eukaryotes. IMPORTANCE Bacteria adapt to environmental challenges by producing intracellular signaling molecules which control downstream pathways and alter cellular processes for survival. Nucleotide second messengers serve to transduce extracellular signals and regulate a wide array of intracellular pathways. Recently, 2´,3´-cyclic nucleotide monophosphates (2´,3´-cNMPs) were identified for contributing to the regulation of cellular pathways in eukaryotes and prokaryotes. In this study we define previously unknown cell processes that are affected by fluctuating 2´,3´-cNMP levels or RNA oligomers with 2´,3´-cyclic phosphate termini in E. coli and Salmonella Typhimurium, providing a framework for studying novel signaling networks in prokaryotes. Furthermore, we utilize metabolomics databases to identify additional prokaryotic and eukaryotic species that generate 2´,3´-cNMPs as a resource for future studies.

scholarly journals RNase I regulates Escherichia coli 2′,3′-cyclic nucleotide monophosphate levels and biofilm formation

2018 ◽  
Vol 475 (8) ◽  
pp. 1491-1506 ◽  
Author(s):  
Benjamin M. Fontaine ◽  
Kevin S. Martin ◽  
Jennifer M. Garcia-Rodriguez ◽  
Claire Jung ◽  
Laura Briggs ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Cyclic Nucleotide ◽  
Biofilm Formation ◽  
Physiological Role ◽  
Rna Degradation ◽  
Bacterial Biofilm ◽  
Biological Functions ◽  
Salvage Pathway ◽  
E Coli

Regulation of nucleotide and nucleoside concentrations is critical for faithful DNA replication, transcription, and translation in all organisms, and has been linked to bacterial biofilm formation. Unusual 2′,3′-cyclic nucleotide monophosphates (2′,3′-cNMPs) recently were quantified in mammalian systems, and previous reports have linked these nucleotides to cellular stress and damage in eukaryotes, suggesting an intriguing connection with nucleotide/nucleoside pools and/or cyclic nucleotide signaling. This work reports the first quantification of 2′,3′-cNMPs in Escherichia coli and demonstrates that 2′,3′-cNMP levels in E. coli are generated specifically from RNase I-catalyzed RNA degradation, presumably as part of a previously unidentified nucleotide salvage pathway. Furthermore, RNase I and 2′,3′-cNMP levels are demonstrated to play an important role in controlling biofilm formation. This work identifies a physiological role for cytoplasmic RNase I and constitutes the first progress toward elucidating the biological functions of bacterial 2′,3′-cNMPs.

Intracellular signaling molecules of nerve tissue progenitors as pharmacological targets for treatment of ethanol-induced neurodegeneration

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gleb Nikolaevich Zyuz’kov ◽  
Larisa Arkad`evna Miroshnichenko ◽  
Elena Vladislavovna Simanina ◽  
Larisa Alexandrovna Stavrova ◽  
Tatyana Yur`evna Polykova
Keyword(s):  
Stem Cells ◽  
Alcohol Abuse ◽  
Intracellular Signaling ◽  
Signaling Molecules ◽  
Growth Potential ◽  
Nerve Tissue ◽  
Intracellular Signaling Molecules

Abstract Objectives The development of approaches to the treatment of neurodegenerative diseases caused by alcohol abuse by targeted pharmacological regulation of intracellular signaling transduction of progenitor cells of nerve tissue is promising. We studied peculiarities of participation of NF-кB-, сАМР/РКА-, JAKs/STAT3-, ERK1/2-, p38-pathways in the regulation of neural stem cells (NSC) and neuronal-committed progenitors (NCP) in the simulation of ethanol-induced neurodegeneration in vitro and in vivo. Methods In vitro, the role of signaling molecules (NF-кB, сАМР, РКА, JAKs, STAT3, ERK1/2, p38) in realizing the growth potential of neural stem cells (NSC) and neuronal-committed progenitors (NCP) in ethanol-induced neurodegeneration modeled in vitro and in vivo was studied. To do this, the method of the pharmacological blockade with the use of selective inhibitors of individual signaling molecules was used. Results Several of fundamental differences in the role of certain intracellular signaling molecules (SM) in proliferation and specialization of NSC and NCP have been revealed. It has been shown that the effect of ethanol on progenitors is accompanied by the formation of a qualitatively new pattern of signaling pathways. Data have been obtained on the possibility of stimulation of nerve tissue regeneration in ethanol-induced neurodegeneration by NF-кB and STAT3 inhibitors. It has been found that the blockage of these SM stimulates NSC and NCP in conditions of ethanol intoxication and does not have a «negative» effect on the realization of the growth potential of intact progenitors (which will appear de novo during therapy). Conclusions The results may serve as a basis for the development of fundamentally new drugs to the treatment of alcoholic encephalopathy and other diseases of the central nervous system associated with alcohol abuse.

scholarly journals Principles of RNA and nucleotide discrimination by the RNA processing enzyme RppH

2020 ◽  
Vol 48 (7) ◽  
pp. 3776-3788 ◽  
Author(s):  
Ang Gao ◽  
Nikita Vasilyev ◽  
Abhishek Kaushik ◽  
Wenqian Duan ◽  
Alexander Serganov
Keyword(s):  
Rna Processing ◽  
Reaction Rates ◽  
Growth Conditions ◽  
Rna Degradation ◽  
Nudix Hydrolase ◽  
X Ray ◽  
E Coli ◽  
Cellular Processes ◽  
Protein Factor ◽  
Hydrolysis Of

Abstract All enzymes face a challenge of discriminating cognate substrates from similar cellular compounds. Finding a correct substrate is especially difficult for the Escherichia coli Nudix hydrolase RppH, which triggers 5′-end-dependent RNA degradation by removing orthophosphate from the 5′-diphosphorylated transcripts. Here we show that RppH binds and slowly hydrolyzes NTPs, NDPs and (p)ppGpp, which each resemble the 5′-end of RNA. A series of X-ray crystal structures of RppH-nucleotide complexes, trapped in conformations either compatible or incompatible with hydrolysis, explain the low reaction rates of mononucleotides and suggest two distinct mechanisms for their hydrolysis. While RppH adopts the same catalytic arrangement with 5′-diphosphorylated nucleotides as with RNA, the enzyme hydrolyzes 5′-triphosphorylated nucleotides by extending the active site with an additional Mg2+ cation, which coordinates another reactive nucleophile. Although the average intracellular pH minimizes the hydrolysis of nucleotides by slowing their reaction with RppH, they nevertheless compete with RNA for binding and differentially inhibit the reactivity of RppH with triphosphorylated and diphosphorylated RNAs. Thus, E. coli RppH integrates various signals, such as competing non-cognate substrates and a stimulatory protein factor DapF, to achieve the differential degradation of transcripts involved in cellular processes important for the adaptation of bacteria to different growth conditions.

scholarly journals Wnt signaling in the thymus is regulated by differential expression of intracellular signaling molecules

2006 ◽  
Vol 103 (9) ◽  
pp. 3322-3326 ◽  
Author(s):  
F. Weerkamp ◽  
M. R. M. Baert ◽  
B. A. E. Naber ◽  
E. E. L. Koster ◽  
E. F. E. de Haas ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Differential Expression ◽  
Intracellular Signaling ◽  
Signaling Molecules ◽  
Intracellular Signaling Molecules

Platelet tetraspanin complexes and their association with lipid rafts

2007 ◽  
Vol 98 (11) ◽  
pp. 1081-1087 ◽  
Author(s):  
Eileen McMillan-Ward ◽  
Sara Israels
Keyword(s):  
Lipid Rafts ◽  
Intracellular Signaling ◽  
Malignant Cell ◽  
Signaling Molecules ◽  
Activated Platelets ◽  
Close Proximity ◽  
Microscopic Studies ◽  
Phosphatidylinositol 4 ◽  
Triton X ◽  
Intracellular Signaling Molecules

SummaryTetraspanins are a superfamily of integral membrane proteins that facilitate the organization of membrane and intracellular signaling molecules into dynamic signaling microdomains, tetraspaninenriched microdomains (TEMs). Four tetraspanin family members have been identified in platelets: CD9, CD151 and TSSC6, which are constitutively associated with αIIb3, and CD63, which is present on granule membranes in resting platelets and associates with αIIbβ3-CD9 following platelet activation. CD63 and CD9 associate with a type II phosphatidylinositol 4-kinase, PI4K55, in both resting and activated platelets. Immunoelectron microscopic studies showed co-localization of CD63 and PI4K55 on internal membranes of resting platelets and on the filopodia of thrombin-activated platelets. Because TEMs in malignant cell lines appear to be distinct from prototypic lipid rafts, this study examined whether CD63-PI4K55 and CD9-PI4K55 complexes were resident in platelet-lipid rafts, or formed distinct microdomains. CD63, CD9 and PI4K55 were recovered from low-density membrane fractions (LDMFs) of sucrose gradients following platelet lysis in Brij 35, but unlike lipidraft proteins were not insoluble in Triton X-100, being absent from LDMFs of platelets lysed with Triton. In cubation of platelets with methyl-β-cyclodextrin, to deplete cholesterol and disrupt lipid rafts, shifted the complexes to higher density sucrose gradient fractions, but did not disrupt the tetraspanin-PI4K55 complexes. These results demonstrate that tetraspanin complexes in platelets form cholesterol-associated microdomains that are distinct from lipid rafts. It is probable thatTEMs and lipid rafts associate under certain conditions, resulting in the close proximity of distinct sets of signaling molecules, facilitating signal transduction.

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