Protein Interaction Networks of Catalytically Active and Catalytically Inactive PqsE in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a human pathogen that relies on quorum sensing to establish infections. The PqsE quorum-sensing protein is required for P. aeruginosa virulence factor production and infection.

The PqsE Active Site as a Target for Small Molecule Antimicrobial Agents against .

The opportunistic pathogen causes antibiotic-resistant, nosocomial infections in immuno-compromised individuals and is a high priority for antimicrobial development. Key to pathogenicity in are biofilm formation and virulence factor production. Both traits are controlled by the cell-to-cell communication process called quorum sensing (QS).

Selective vulnerabilities in the proteostasis network of castration-resistant prostate cancer.

Castration-resistant prostate cancer (CRPC) is associated with an increased reliance on heat shock protein 70 (HSP70), but it is not clear what other protein homeostasis (proteostasis) factors might be involved. To address this question, we performed functional and synthetic lethal screens in four prostate cancer cell lines. These screens confirmed key roles for HSP70, HSP90, and their co-chaperones, but also suggested that the mitochondrial chaperone, HSP60/HSPD1, is selectively required in CRPC cell lines.

The PqsE-RhlR Interaction Regulates RhlR DNA Binding to Control Virulence Factor Production in .

Pseudomonas aeruginosa is an opportunistic pathogen that causes disease in immunocompromised individuals and individuals with underlying pulmonary disorders. P. aeruginosa virulence is controlled by quorum sensing (QS), a bacterial cell-cell communication mechanism that underpins transitions between individual and group behaviors.

Inhibitor Mimetic Mutations in the PqsE Enzyme Reveal a Protein-Protein Interaction with the Quorum-Sensing Receptor RhlR That Is Vital for Virulence Factor Production.

is an opportunistic human pathogen that causes fatal infections. There exists an urgent need for new antimicrobial agents to combat . We conducted a screen for molecules that bind the virulence-controlling protein PqsE and characterized hit compounds for inhibition of PqsE enzymatic activity.

Functional genomics screen identifies proteostasis targets that modulate prion protein (PrP) stability.

Prion protein (PrP) adopts either a helical conformation (PrP) or an alternative, beta sheet-rich, misfolded conformation (PrP). The PrP form has the ability to "infect" PrP and force it into the misfolded state. Accumulation of PrP is associated with a number of lethal neurodegenerative disorders, including Creutzfeldt-Jacob disease (CJD).

Tryptophan scanning mutagenesis as a way to mimic the compound-bound state and probe the selectivity of allosteric inhibitors in cells.

Understanding the selectivity of a small molecule for its target(s) in cells is an important goal in chemical biology and drug discovery. One powerful way to address this question is with dominant negative (DN) mutants, in which an active site residue in the putative target is mutated. While powerful, this approach is less straightforward for allosteric sites.

Discovery of PqsE Thioesterase Inhibitors for Using DNA-Encoded Small Molecule Library Screening.

is a leading cause of hospital-acquired infections in the United States. PqsE, a thioesterase enzyme, is vital for virulence of , making PqsE an attractive target for inhibition. Neither the substrate nor the product of PqsE catalysis has been identified.

A Legionella pneumophila Kinase Phosphorylates the Hsp70 Chaperone Family to Inhibit Eukaryotic Protein Synthesis.

Legionella pneumophila (L.p.), the microbe responsible for Legionnaires' disease, secretes ∼300 bacterial proteins into the host cell cytosol.

A Local Allosteric Network in Heat Shock Protein 70 (Hsp70) Links Inhibitor Binding to Enzyme Activity and Distal Protein-Protein Interactions.

Allosteric inhibitors can be more difficult to optimize without an understanding of how their binding influences the conformational motions of the target. Here, we used an integrated computational and experimental approach to probe the molecular mechanism of an allosteric inhibitor of heat shock protein 70 (Hsp70). The anticancer compound, MKT-077, is known to bind a conserved site in members of the Hsp70 family, which favors the ADP-bound state and interferes with a protein-protein interaction (PPI) at long range.

The disorderly conduct of Hsc70 and its interaction with the Alzheimer's-related Tau protein.

Hsp70 chaperones bind to various protein substrates for folding, trafficking, and degradation. Considerable structural information is available about how prokaryotic Hsp70 (DnaK) binds substrates, but less is known about mammalian Hsp70s, of which there are 13 isoforms encoded in the human genome. Here, we report the interaction between the human Hsp70 isoform heat shock cognate 71-kDa protein (Hsc70 or HSPA8) and peptides derived from the microtubule-associated protein Tau, which is linked to Alzheimer's disease.

High-throughput screen for inhibitors of protein-protein interactions in a reconstituted heat shock protein 70 (Hsp70) complex.

Protein-protein interactions (PPIs) are an important category of putative drug targets. Improvements in high-throughput screening (HTS) have significantly accelerated the discovery of inhibitors for some categories of PPIs. However, methods suitable for screening multiprotein complexes ( those composed of three or more different components) have been slower to emerge.

Targeting Allosteric Control Mechanisms in Heat Shock Protein 70 (Hsp70).

Heat shock protein 70 (Hsp70) is a molecular chaperone that plays critical roles in protein homeostasis. Hsp70's chaperone activity is coordinated by intra-molecular interactions between its two domains, as well as inter-molecular interactions between Hsp70 and its co-chaperones. Each of these contacts represents a potential opportunity for the development of chemical inhibitors.

RNA binding and inhibition of primer extension by a Ru(III)/Pt(II) metal complex.

AH197, a trinuclear Ru(III)/Pt(II) metal complex, is strikingly more effective than the hallmark anticancer drug cisplatin and the Ru(III) clinical candidate NAMI-A in its binding to RNA and inhibition of primer DNA synthesis. Heteromultinuclear complexes could potentially serve as far better chemotherapeutics than mononuclear complexes.

Hetero-multinuclear ruthenium(III)/platinum(II) complexes that potentially exhibit both antimetastatic and antineoplastic properties.

Hetero-multinuclear, platinum/ruthenium species were synthesized and tested for their effect on the motility of A549 (nonsmall cell lung) and MDA-MB-231 (breast) cancer cells and for their ability to inhibit DNA mobility using gel electrophoresis. It was found that the Ru(2)Pt trinuclear species [Na(2)]{[Ru(III)Cl(4)(DMSO-S)(-μ-pyz)](2)Pt(II)Cl(2)}, AH197, was much more efficient at inhibiting cell motility than [C(3)N(2)H(5)][Ru(III)Cl(4)(DMSO-S)(C(3)N(2)H(4))], NAMI-A, while the dinuclear RuPt species [K][Ru(III)Cl(4)(DMSO-S)(-μ-pyz)Pt(II)(DMSO-S)Cl(2)], IT127, was slightly better than NAMI-A. However, the dinuclear species retarded the electrophoretic mobility of DNA greater than both the trinuclear complex and cisplatin.