Cyclic di-GMP activation of polynucleotide phosphorylase signal-dependent RNA processing.
ABSTRACT The second messenger cyclic diguanylic acid (c-di-GMP) is implicated in key lifestyle decisions of bacteria, including biofilm formation and changes in motility and virulence. Some challenges in deciphering the physiological roles of c-di-GMP are the limited knowledge about the cellular targets of c-di-GMP, the signals that control its levels, and the proportion of free cellular c-di-GMP, if any. Here, we identify the target and the regulatory signal for a c-di-GMP-responsive Escherichia coli ribonucleoprotein complex. We show that a direct c-di-GMP target in E. coli is polynucleotide phosphorylase (PNPase), an important enzyme in RNA metabolism that serves as a 3' polyribonucleotide polymerase or a 3'-to-5' exoribonuclease. We further show that a complex of polynucleotide phosphorylase with the direct oxygen sensors DosC and DosP can perform oxygen-dependent RNA processing. We conclude that c-di-GMP can mediate signal-dependent RNA processing and that macromolecular complexes can compartmentalize c-di-GMP signaling.
SourceAvailable from: Lina María Ruiz Hincapié[Show abstract] [Hide abstract]
ABSTRACT: An understanding of biofilm formation is relevant to the design of biological strategies to improve the efficiency of the bioleaching process and to prevent environmental damages caused by acid mine/rock drainage. For this reason, our laboratory is focused on the characterization of the molecular mechanisms involved in biofilm formation in different biomining bacteria. In many bacteria, the intracellular levels of c-di-GMP molecules regulate the transition from the motile planktonic state to sessile community-based behaviors, such as biofilm development, through different kinds of effectors. Thus, we recently started a study of the c-di-GMP pathway in several biomining bacteria including Acidithiobacillus caldus. C-di-GMP molecules are synthesized by diguanylate cyclases (DGCs) and degraded by phosphodiesterases (PDEs). We previously reported the existence of intermediates involved in c-di-GMP pathway from different Acidithiobacillus species. Here, we report our work related to At. caldus ATCC 51756. We identified several putative-ORFs encoding DGC and PDE and effector proteins. By using total RNA extracted from At. caldus cells and RT-PCR, we demonstrated that these genes are expressed. We also demonstrated the presence of c-di-GMP by mass spectrometry and showed that genes for several of the DGC enzymes were functional by heterologous genetic complementation in Salmonella enterica serovar Typhimurium mutants. Moreover, we developed a DGC defective mutant strain (Δc1319) that strongly indicated that the c-di-GMP pathway regulates the swarming motility and adherence to sulfur surfaces by At. caldus. Together, our results revealed that At. caldus possesses a functional c-di-GMP pathway which could be significant for ores colonization during the bioleaching process.PLoS ONE 02/2015; 10(2):e0116399. DOI:10.1371/journal.pone.0116399 · 3.53 Impact Factor
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ABSTRACT: Escherichia coli Direct Oxygen Sensor (Ec DOS, also known as Ec DosP) is a heme-based O2-sensing phosphodiesterase from Escherichia coli that catalyzes the conversion of cyclic-di-GMP to linear di-GMP. Cyclic-di-GMP is an important second messenger in bacteria, highlighting the importance of understanding structure-function relationships of Ec DOS. Ec DOS is composed of an N-terminal heme-bound O2-sensing PAS domain and a C-terminal phosphodiesterase catalytic domain. Notably, its activity is markedly enhanced by O2 binding to the heme Fe(II) complex in the PAS sensor domain. X-ray crystal structures and spectroscopic and catalytic characterization of the wild-type and mutant proteins have provided important structural and functional clues to understanding the molecular mechanism of intramolecular catalytic regulation by O2 binding. This review summarizes the intriguing findings that have obtained for Ec DOS.
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ABSTRACT: The chaperone protein HSPA5/Dna K is conserved throughout evolution from higher eukaryotes down to prokaryotes. The celecoxib derivative OSU-03012 (also called AR-12) interacts with Viagra or Cialis in eukaryotic cells to rapidly reduce HSPA5 levels as well as blunt the functions of many other chaperone proteins. Because multiple chaperones are modulated in eukaryotes, the expression of cell surface virus receptors is reduced and because HSPA5 in blocked viruses cannot efficiently replicate. Because DnaK levels are reduced in prokaryotes by OSU-03012, the levels of DnaK chaperone proteins such as Rec A decline, which is associated with bacterial cell death and a resensitization of so-called drug-resistant superbugs to standard of care antibiotics. In Alzheimer's disease, HSPA5 has been shown to play a supportive role for the progression of tau phosphorylation and neurodegeneration. Thus, in eukaryotes, HSPA5 represents a target for anticancer, antiviral, and anti-Alzheimer's therapeutics and in prokaryotes, DnaK and bacterial phosphodiesterases represent novel antibiotic targets that should be exploited in the future by pharmaceutical companies.DNA and Cell Biology 03/2015; 34(3):153-8. DOI:10.1089/dna.2015.2808 · 1.99 Impact Factor