Effects of TRPC1's Lysines on Heteromeric TRPC5-TRPC1 Channel Function.

Background: TRPC5 proteins form plasma membrane cation channels and are expressed in the nervous and cardiovascular systems. TRPC5 activation leads to cell depolarization and increases neuronal excitability, whereas a homologous TRPC1 inhibits TRPC5 function via heteromerization. The mechanism underlying the inhibitory effect of TRPC1 in TRPC5/TRPC1 heteromers remains unknown.

Targeting Specific Kinase Substrates Rescues Increased Colitis Severity Induced by the Crohn's Disease-Linked LRRK2-N2081D Variant.

LRRK2 contains a kinase domain where both the N2081D Crohn's disease (CD) risk and the G2019S Parkinson's disease (PD)-pathogenic variants are located. The mechanisms by which the N2081D variant increase CD risk, and how these adjacent mutations result in distinct diseases, remain unclear. To investigate the pathophysiology of the CD-linked LRRK2 N2081D variant, we generated a knock-in (KI) mouse model and compared its effects to those of the LRRK2-G2019S mutation.

Longitudinal IgG antibody responses to Plasmodium vivax blood-stage antigens during and after acute vivax malaria in individuals living in the Brazilian Amazon.

Background: To make progress towards malaria elimination, a highly effective vaccine targeting Plasmodium vivax is urgently needed. Evaluating the kinetics of natural antibody responses to vaccine candidate antigens after acute vivax malaria can inform the design of serological markers of exposure and vaccines.

Methodology/principal Findings: The responses of IgG antibodies to 9 P.

Roc, the G-domain of the Parkinson's disease-associated protein LRRK2.

Mutation in leucine-rich repeat (LRR) kinase 2 (LRRK2) is a common cause of Parkinson's disease (PD). Aberrant LRRK2 kinase activity is associated with disease pathogenesis and thus it is an attractive drug target for combating PD. Intense efforts in the past nearly two decades have focused on the development of small-molecule inhibitors of the kinase domain of LRRK2 and have identified potent kinase inhibitors.

Allosteric differences dictate GroEL complementation of E. coli.

GroES/GroEL is the only bacterial chaperone essential under all conditions, making it a potential antibiotic target. Rationally targeting ESKAPE GroES/GroEL as an antibiotic strategy necessitates studying their structure and function. Herein, we outline the structural similarities between Escherichia coli and ESKAPE GroES/GroEL and identify significant differences in intra- and inter-ring cooperativity, required in the refolding cycle of client polypeptides.

A new alpha-synuclein missense variant (Thr72Met) in two Turkish families with Parkinson's disease.

Introduction: Missense variants and multiplications of the alpha-synuclein gene (SNCA) are established as rare causes of autosomal dominant forms of Parkinson's Disease (PD).

Methods: Two families of Turkish origins with PD were studied; the SNCA coding region was analyzed by Sanger sequencing, and by whole exome sequencing (WES) in the index patient of the first and the second family, respectively. Co-segregation studies and haplotype analysis across the SNCA locus were carried out.

Functional Differences between E. coli and ESKAPE Pathogen GroES/GroEL.

As the GroES/GroEL chaperonin system is the only bacterial chaperone that is essential under all conditions, we have been interested in the development of GroES/GroEL inhibitors as potential antibiotics. Using GroES/GroEL as a surrogate, we have discovered several classes of GroES/GroEL inhibitors that show potent antibacterial activity against both Gram-positive and Gram-negative bacteria. However, it remains unknown if GroES/GroEL is functionally identical to other GroES/GroEL chaperonins and hence if our inhibitors will function against other chaperonins.

Analogs of nitrofuran antibiotics are potent GroEL/ES inhibitor pro-drugs.

In two previous studies, we identified compound 1 as a moderate GroEL/ES inhibitor with weak to moderate antibacterial activity against Gram-positive and Gram-negative bacteria including Bacillus subtilis, methicillin-resistant Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, and SM101 Escherichia coli (which has a compromised lipopolysaccharide biosynthetic pathway making bacteria more permeable to drugs). Extending from those studies, we developed two series of analogs with key substructures resembling those of known antibacterials, nitroxoline (hydroxyquinoline moiety) and nifuroxazide/nitrofurantoin (bis-cyclic-N-acylhydrazone scaffolds). Through biochemical and cell-based assays, we identified potent GroEL/ES inhibitors that selectively blocked E.

Dual-targeting GroEL/ES chaperonin and protein tyrosine phosphatase B (PtpB) inhibitors: A polypharmacology strategy for treating Mycobacterium tuberculosis infections.

Current treatments for Mycobacterium tuberculosis infections require long and complicated regimens that can lead to patient non-compliance, increasing incidences of antibiotic-resistant strains, and lack of efficacy against latent stages of disease. Thus, new therapeutics are needed to improve tuberculosis standard of care. One strategy is to target protein homeostasis pathways by inhibiting molecular chaperones such as GroEL/ES (HSP60/10) chaperonin systems.

HSP60/10 chaperonin systems are inhibited by a variety of approved drugs, natural products, and known bioactive molecules.

All living organisms contain a unique class of molecular chaperones called 60 kDa heat shock proteins (HSP60 - also known as GroEL in bacteria). While some organisms contain more than one HSP60 or GroEL isoform, at least one isoform has always proven to be essential. Because of this, we have been investigating targeting HSP60 and GroEL chaperonin systems as an antibiotic strategy.

Parkinson's disease-associated mutations in the GTPase domain of LRRK2 impair its nucleotide-dependent conformational dynamics.

Mutation in leucine-rich repeat kinase 2 (LRRK2) is a common cause of familial Parkinson's disease (PD). Recently, we showed that a disease-associated mutation R1441H rendered the GTPase domain of LRRK2 catalytically less active and thereby trapping it in a more persistently "on" conformation. However, the mechanism involved and characteristics of this on conformation remained unknown.

The Parkinson's disease-associated mutation N1437H impairs conformational dynamics in the G domain of LRRK2.

Parkinson disease-associated mutations within the GTPase domain Ras of complex proteins (ROC) of leucine rich repeat kinase 2 (LRRK2) result in an abnormal over-activation of its kinase domain. However, the mechanisms involved remain unclear. Recent study has shown that LRRK2 G-domain cycles between monomeric and dimeric conformations upon binding to GTP or guanosine diphosphate, and that the Parkinson's disease (PD)-associated R1441C/G/H mutations impair the G-domain monomer-dimer dynamics and trap the G-domain in a constitutive monomeric conformation.

Roco Proteins and the Parkinson's Disease-Associated LRRK2.

Small G-proteins are structurally-conserved modules that function as molecular on-off switches. They function in many different cellular processes with differential specificity determined by the unique effector-binding surfaces, which undergo conformational changes during the switching action. These switches are typically standalone monomeric modules that form transient heterodimers with specific effector proteins in the 'on' state, and cycle to back to the monomeric conformation in the 'off' state.

Hydroxybiphenylamide GroEL/ES Inhibitors Are Potent Antibacterials against Planktonic and Biofilm Forms of Staphylococcus aureus.

We recently reported the identification of a GroEL/ES inhibitor (1, N-(4-(benzo[ d]thiazol-2-ylthio)-3-chlorophenyl)-3,5-dibromo-2-hydroxybenzamide) that exhibited in vitro antibacterial effects against Staphylococcus aureus comparable to vancomycin, an antibiotic of last resort. To follow up, we have synthesized 43 compound 1 analogs to determine the most effective functional groups of the scaffold for inhibiting GroEL/ES and killing bacteria. Our results identified that the benzothiazole and hydroxyl groups are important for inhibiting GroEL/ES-mediated folding functions, with the hydroxyl essential for antibacterial effects.

Constructing Kinetically Controlled Denaturation Isotherms of Folded Proteins Using Denaturant-Pulse Chaperonin Binding.

Methods to assess the kinetic stability of proteins, particularly those that are aggregation prone, are very useful in establishing ligand induced stabilizing effects. Because aggregation prone proteins are by nature difficult to work with, most solution based methods are compromised by this inherent instability. Here, we describe a label-free method that examines the denaturation of immobilized proteins where the dynamic unfolded protein populations are captured and detected by chaperonin binding.

Discovery and Optimization of Inhibitors of the Parkinson's Disease Associated Protein DJ-1.

DJ-1 is a Parkinson's disease associated protein endowed with enzymatic, redox sensing, regulatory, chaperoning, and neuroprotective activities. Although DJ-1 has been vigorously studied for the past decade and a half, its exact role in the progression of the disease remains uncertain. In addition, little is known about the spatiotemporal regulation of DJ-1, or the biochemical basis explaining its numerous biological functions.

Sulfonamido-2-arylbenzoxazole GroEL/ES Inhibitors as Potent Antibacterials against Methicillin-Resistant Staphylococcus aureus (MRSA).

Extending from a study we recently published examining the antitrypanosomal effects of a series of GroEL/ES inhibitors based on a pseudosymmetrical bis-sulfonamido-2-phenylbenzoxazole scaffold, here, we report the antibiotic effects of asymmetric analogs of this scaffold against a panel of bacteria known as the ESKAPE pathogens ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). While GroEL/ES inhibitors were largely ineffective against K. pneumoniae, A.

Crystal structure of the DNA binding domain of the transcription factor T-bet suggests simultaneous recognition of distant genome sites.

The transcription factor T-bet (Tbox protein expressed in T cells) is one of the master regulators of both the innate and adaptive immune responses. It plays a central role in T-cell lineage commitment, where it controls the T1 response, and in gene regulation in plasma B-cells and dendritic cells. T-bet is a member of the Tbox family of transcription factors; however, T-bet coordinately regulates the expression of many more genes than other Tbox proteins.

Reducing C-terminal truncation mitigates synucleinopathy and neurodegeneration in a transgenic model of multiple system atrophy.

Multiple system atrophy (MSA) is a sporadic orphan neurodegenerative disorder. No treatment is currently available to slow down the aggressive neurodegenerative process, and patients die within a few years after disease onset. The cytopathological hallmark of MSA is the accumulation of alpha-synuclein (α-syn) aggregates in affected oligodendrocytes.

Caspase-1 causes truncation and aggregation of the Parkinson's disease-associated protein α-synuclein.

The aggregation of α-synuclein (aSyn) leading to the formation of Lewy bodies is the defining pathological hallmark of Parkinson's disease (PD). Rare familial PD-associated mutations in aSyn render it aggregation-prone; however, PD patients carrying wild type (WT) aSyn also have aggregated aSyn in Lewy bodies. The mechanisms by which WT aSyn aggregates are unclear.

Structural and Biochemical Characterization of AidC, a Quorum-Quenching Lactonase with Atypical Selectivity.

Quorum-quenching catalysts are of interest for potential application as biochemical tools for interrogating interbacterial communication pathways, as antibiofouling agents, and as anti-infective agents in plants and animals. Herein, the structure and function of AidC, an N-acyl-l-homoserine lactone (AHL) lactonase from Chryseobacterium, is characterized. Steady-state kinetics show that zinc-supplemented AidC is the most efficient wild-type quorum-quenching enzymes characterized to date, with a kcat/KM value of approximately 2 × 10(6) M(-1) s(-1) for N-heptanoyl-l-homoserine lactone.

Potential pharmacological chaperones targeting cancer-associated MCL-1 and Parkinson disease-associated α-synuclein.

Pharmacological chaperones are small molecules that bind to proteins and stabilize them against thermal denaturation or proteolytic degradation, as well as assist or prevent certain protein-protein assemblies. These activities are being exploited for the development of treatments for diseases caused by protein instability and/or aberrant protein-protein interactions, such as those found in certain forms of cancers and neurodegenerative diseases. However, designing or discovering pharmacological chaperones for specific targets is challenging because of the relatively featureless protein target surfaces, the lack of suitable chemical libraries, and the shortage of efficient high-throughput screening methods.

Thermodynamic and structural characterization of the specific binding of Zn(II) to human protein DJ-1.

Mutations of DJ-1 cause familial Parkinson's disease (PD), although the role of DJ-1 in PD remains unresolved. Very recent reports have shown that DJ-1 interacts with copper ions. This evidence opens new avenues to understanding the function of DJ-1 and its role in PD.