Honeybee CaV4 has distinct permeation, inactivation, and pharmacology from homologous NaV channels.

DSC1, a Drosophila channel with sequence similarity to the voltage-gated sodium channel (NaV), was identified over 20 years ago. This channel was suspected to function as a non-specific cation channel with the ability to facilitate the permeation of calcium ions (Ca2+). A honeybee channel homologous to DSC1 was recently cloned and shown to exhibit strict selectivity for Ca2+, while excluding sodium ions (Na+), thus defining a new family of Ca2+ channels, known as CaV4.

Functional Characterization of Four Known Cav2.1 Variants Associated with Neurodevelopmental Disorders.

Cav2.1 channels are expressed throughout the brain and are the predominant Ca channels in the Purkinje cells. These cerebellar neurons fire spontaneously, and Cav2.

Importance of the Choice of a Recombinant System to Produce Large Amounts of Functional Membrane Protein hERG.

Human ether-a-gogo related gene (hERG) product is the membrane potassium channel Kv11.1, which is involved in the electrical activity of the heart. As such, it is a key player in the toxicity of many drug candidates.

Fluorescent analogues of BeKm-1 with high and specific activity against the hERG channel.

Peptidic toxins that target specifically mammalian channels and receptors can be found in the venom of animals. These toxins are rarely used directly as tools for biochemical experiments, and need to be modified via the attachment of chemical groups (e.g.

Suppression of breast cancer metastasis through the inactivation of ADP-ribosylation factor 1.

Metastasis is the major cause of cancer-related death in breast cancer patients, which is controlled by specific sets of genes. Targeting these genes may provide a means to delay cancer progression and allow local treatment to be more effective. We report for the first time that ADP-ribosylation factor 1 (ARF1) is the most amplified gene in ARF gene family in breast cancer, and high-level amplification of ARF1 is associated with increased mRNA expression and poor outcomes of patients with breast cancer.

Developments in SPR Fragment Screening.

Introduction: Fragment-based approaches have played an increasing role alongside high-throughput screening in drug discovery for 15 years. The label-free biosensor technology based on surface plasmon resonance (SPR) is now sensitive and informative enough to serve during primary screens and validation steps.

Areas Covered: In this review, the authors discuss the role of SPR in fragment screening.

Uneven HAK/KUP/KT Protein Diversity Among Angiosperms: Species Distribution and Perspectives.

HAK/KUP/KT K(+) transporters have been widely associated with K(+) transport across membranes in bacteria, fungi, and plants. Indeed some members of the plant HAK/KUP/KT family contribute to root K(+) uptake, notably at low external concentrations. Besides such role in acquisition, several studies carried out in Arabidopsis have shown that other members are also involved in developmental processes.

Isolation and characterization of a new Bacillus thuringiensis strain Lip harboring a new cry1Aa gene highly toxic to Ephestia kuehniella (Lepidoptera: Pyralidae) larvae.

The aim of this study was to characterize new Bacillus thuringiensis strains that have a potent insecticidal activity against Ephestia kuehniella larvae. Strains harboring cry1A genes were tested for their toxicity, and the Lip strain showed a higher insecticidal activity compared to that of the reference strain HD1 (LC50 of Lip and HD1 were 33.27 and 128.

Distinct amino acids in the C-linker domain of the Arabidopsis K+ channel KAT2 determine its subcellular localization and activity at the plasma membrane.

Shaker K(+) channels form the major K(+) conductance of the plasma membrane in plants. They are composed of four subunits arranged around a central ion-conducting pore. The intracellular carboxy-terminal region of each subunit contains several regulatory elements, including a C-linker region and a cyclic nucleotide-binding domain (CNBD).

Fragment-based identification of a locus in the Sec7 domain of Arno for the design of protein-protein interaction inhibitors.

By virtual screening using a fragment-based drug design (FBDD) approach, 33 fragments were selected within small pockets around interaction hot spots on the Sec7 surface of the nucleotide exchange factor Arno, and then their ability to interfere with the Arno-catalyzed nucleotide exchange on the G-protein Arf1 was evaluated. By use of SPR, NMR, and fluorescence assays, the direct binding of three of the identified fragments to Arno Sec7 domain was demonstrated and the promiscuous aggregate behavior evaluated. Then the binding mode of one fragment and of a more active analogue was solved by X-ray crystallography.

Kinetics of interaction between ADP-ribosylation factor-1 (Arf1) and the Sec7 domain of Arno guanine nucleotide exchange factor, modulation by allosteric factors, and the uncompetitive inhibitor brefeldin A.

The GDP/GTP nucleotide exchange of Arf1 is catalyzed by nucleotide exchange factors (GEF), such as Arno, which act through their catalytic Sec7 domain. This exchange is a complex mechanism that undergoes conformational changes and intermediate complex species involving several allosteric partners such as nucleotides, Mg(2+), and Sec7 domains. Using a surface plasmon resonance approach, we characterized the kinetic binding parameters for various intermediate complexes.

Development of tripartite polyion micelles for efficient peptide delivery into dendritic cells without altering their plasticity.

For many years, a great deal of interest has been focusing on the optimization of peptide presentation by dendritic cells (DCs) using peptide-encapsulated particles, in order to enhance the immune response. Nowadays, DCs are also known to be involved in peripheral tolerance, inducing anergy or regulatory T lymphocytes. To preserve the plasticity of DCs, we formulated non-cytotoxic pH-sensitive polyion complex micelles based on an original tripartite association of polymethacrylic acid-b-polyethylene oxide, poly-L-lysine and fluorescent-peptide: OVAFITC peptide, as a model drug.

N-1H-benzimidazol-5-ylbenzenesulfonamide derivatives as potent hPXR agonists.

The Human Pregnane X Receptor (hPXR) is a nuclear receptor that regulates the expression of phase I and phase II drug-metabolizing enzymes, as well as that of drug transporters. Because this receptor plays a critical role in protecting tissues from potentially toxic endo- and xenobiotics, highly active agonists could represent novel therapeutic tools in treating several human diseases. Using an in vitro screening reporter system that allow to characterize hPXR activators and a first step of chemical modifications of an original agonist ligand (C2BA-4, 1-(2-chlorophenyl)-N-[1-(1-phenylethyl)-1H-benzimidazol-5-yl]methanesulfonamide), we identified compounds with a N-1H-benzimidazol-5-ylbenzenesulfonamide scaffold as a potent family of hPXR agonists.

Structure-activity relationships of Bak derived peptides: affinity and specificity modulations by amino acid replacement.

To study the structure-activity relationships (SAR) and the binding activity of pro-apoptotic Bak BH3 domain, we synthesised several 16mer peptide analogues corresponding to the region (72)-GQVGRQLAIIGDDINR-(87). Using different amino acids varying in length, steric and electronic properties, we investigated the role and the nature of physicochemical parameters of residues Val74, Leu78, Ile81 and Ile85, previously identified to be crucial for interactions. With this aim, we measured the affinity of these peptides on two anti-apoptotic proteins Bcl-x(L) and Bcl-2 by a polarization fluorescence competitive assay.

Discovery of a highly active ligand of human pregnane x receptor: a case study from pharmacophore modeling and virtual screening to "in vivo" biological activity.

The human pregnane X receptor (hPXR) is a nuclear receptor that regulates the expression of phase I and II drug-metabolizing enzymes as well as that of drug transporters. In addition, this receptor plays a critical role in cholesterol homeostasis and in protecting tissues from potentially toxic endobiotics. hPXR is activated by a broad spectrum of low-affinity compounds including xenobiotics and endobiotics such as bile acids and their precursors.

Structure-based discovery of an inhibitor of Arf activation by Sec7 domains through targeting of protein-protein complexes.

Small molecules that produce nonfunctional protein-protein complexes are an alternative to competitive inhibitors for the inhibition of protein functions. Here we target the activation of the small GTP-binding protein Arf1, a major regulator of membrane traffic, by the Sec7 catalytic domain of its guanine nucleotide exchange factor ARNO. The crystal structure of the Arf1-GDP/ARNO complex, which initiates the exchange reaction, was used to discover an inhibitor, LM11, using in silico screening of a flexible pocket near the Arf1/ARNO interface.

Structure-based design, synthesis, and biological evaluation of novel inhibitors of human cyclophilin A.

Cyclophilin A is involved in many cellular processes, including protein folding and intracellular transports. Because cyclophilin A has been shown to interact with HIV-1 gag proteins and to enhance the viral infectivity, nonimmunosuppressive cyclophilin A ligands may represent a new class of therapeutic agents against HIV. Here, we report a virtual screening using structure- and pharmacophore-based design to identify original nonpeptidic cyclophilin ligands.

S 23521 decreases food intake and body weight gain in diet-induced obese rats.

Objective: To investigate the effect of S 23521, a new glucagon-like peptide-1-(7-36) amide analogue, on food intake and body weight gain in obese rats, as well as on gene expression of several proteins involved in energy homeostasis.

Research Methods And Procedures: Lean and diet-induced obese rats were treated with either S 23521 or vehicle. S 23521 was given either intraperitoneally (10 or 100 microg/kg) or subcutaneously (100 microg/kg) for 14 and 20 days, respectively.

Structural requirements of the N-terminal region of GLP-1-[7-37]-NH2 for receptor interaction and cAMP production.

A series of GLP-1-[7-36]-NH(2) (tGLP-1) and GLP-1-[7-37] analogs modified in position 7, 8, 9 and 36, have been designed and evaluated on murine GLP-1 receptors expressed in RIN T3 cells for both their affinity and activity. Ten of the synthesized peptides were found full agonists with activities superior or at least equal to that of the native hormone. Five of them were investigated for their plasmatic stability and the most stable, [a(8)-desR(36)]GLP-1-[7-37]- NH(2) (Compound 8), evaluated in vivo in a glucose tolerance test which confirmed a clearly longer activity than that of the native hormone.

Amino-acid changes acquired during evolution by olfactory receptor 912-93 modify the specificity of odorant recognition.

The sense of smell in mammals can perceive and discriminate a wide variety of volatile odorants. Odorants bind to specific olfactory receptors (ORs) to initiate an action potential that transduces olfactory information to the olfactory cortex. We previously identified the structural motifs of odorant molecules (aliphatic 2- or 3-ketones) required to activate mouse OR912-93 by detection of the odorant response using calcium measurement in transfected cells.

The H-NS dimerization domain defines a new fold contributing to DNA recognition.

H-NS, a protein found in Gram-negative bacteria, is involved in structuring the bacterial chromosome and acts as a global regulator for the expression of a wide variety of genes. These functions are correlated with both its DNA-binding and oligomerization properties. We have identified the minimal dimerization domain of H-NS, a 46 amino acid-long N-terminal fragment, and determined its structure using heteronuclear NMR spectroscopy.

BIGH3 (TGFBI) Arg124 mutations influence the amyloid conversion of related peptides in vitro.

Amyloid deposits with Arg124 mutated TGFBI protein have been identified in autosomal dominant blinding corneal dystrophies. We assessed in vitro the mechanisms determining TGFBI protein amyloid transformation involving mutations of Arg124. Eight peptides synthesized following the TGFBI protein sequence, centered on codon Arg124 holding the previously reported amyloidogenic mutations and the respective controls were studied.

Overexpression and structural study of the cathelicidin motif of the protegrin-3 precursor.

Numerous precursors of antibacterial peptides with unrelated sequences share a similar prosequence of 96-101 residues, referred to as the cathelicidin motif. The structure of this widespread motif has not yet been reported. The cathelicidin motif of protegrin-3 (ProS) was overexpressed in Escherichia coli as a His-tagged protein to facilitate its purification.