Mpox disease was reported in 110 countries since May 2022, with 88,026 cases and 148 deaths by 21 June 2023. Although some drugs were already approved for Mpox treatment, the available smallpox vaccines can provide 85% cross-prevention, but there are no scientific publications describing the patent portfolio for Mpox vaccines. This paper aims to contribute to the identification of the status of the smallpox vaccine patents now applied for Mpox.
View Article and Find Full Text PDFPlasmodium falciparum is the parasite responsible for the most severe form of malaria. Its increasing resistance to existing antimalarials represents a major threat to human health and urges the development of new therapeutic strategies to fight malaria. The proteasome is a protease complex essential in all eukaryotes.
View Article and Find Full Text PDFThe proteasome is a multi-component protease complex responsible for regulating key processes such as the cell cycle and antigen presentation. Compounds that target the proteasome are potentially valuable tools for the treatment of pathogens that depend on proteasome function for survival and replication. In particular, proteasome inhibitors have been shown to be toxic for the malaria parasite Plasmodium falciparum at all stages of its life cycle.
View Article and Find Full Text PDFThe proteasome is a highly regulated protease complex fundamental for cell homeostasis and controlled cell cycle progression. It functions by removing a wide range of specifically tagged proteins, including key cellular regulators. Here we present the structure of the human 20S proteasome core bound to a substrate analogue inhibitor molecule, determined by electron cryo-microscopy (cryo-EM) and single-particle analysis at a resolution of around 3.
View Article and Find Full Text PDFUnlabelled: Epilepsy compromises the development of cognitive and social skills and represents a risk of psychiatric comorbidity.
Objective: To compare psychopathological symptoms in children with epilepsy and in a healthy group, and to correlate the results with neuropsychological and clinical variables.
Method: Forty five children with idiopathic epilepsy and sixty five healthy controls underwent neuropsychological evaluation and their caregivers replied to a psychopathology questionnaire (Child Behavior Checklist - CBCL).
Acta Crystallogr D Biol Crystallogr
November 2013
The anaphase-promoting complex (APC/C) is a large E3 ubiquitin ligase that regulates progression through specific stages of the cell cycle by coordinating the ubiquitin-dependent degradation of cell-cycle regulatory proteins. Depending on the species, the active form of the APC/C consists of 14-15 different proteins that assemble into a 20-subunit complex with a mass of approximately 1.3 MDa.
View Article and Find Full Text PDFWe have combined alanine mutagenesis and functional assays to identify amino acid residues in the channel domain that are critical for inositol 1,4,5-trisphosphate receptor (IP(3)R) channel function. The residues selected were highly conserved in all three IP(3)R isoforms and were located in the cytosolic end of the S6 pore-lining helix and proximal portion of the C-tail. Two adjacent hydrophobic amino acids (Ile-2588 and Ile-2589) at the putative cytosolic interface of the S6 helix inactivated channel function and could be candidates for the channel gate.
View Article and Find Full Text PDFMechanistic and structural studies of large multi-subunit assemblies are greatly facilitated by their reconstitution in heterologous recombinant systems. In the present paper, we describe the generation of recombinant human APC/C (anaphase-promoting complex/cyclosome), an E3 ubiquitin ligase that regulates cell-cycle progression. Human APC/C is composed of 14 distinct proteins that assemble into a complex of at least 19 subunits with a combined molecular mass of ~1.
View Article and Find Full Text PDFSkp1-Cul1-Fbox (SCF) E3 ligases are activated by ligation to the ubiquitin-like protein Nedd8, which is reversed by the deneddylating Cop9 signalosome (CSN). However, CSN also promotes SCF substrate turnover through unknown mechanisms. Through biochemical and electron microscopy analyses, we determined molecular models of CSN complexes with SCF(Skp2/Cks1) and SCF(Fbw7) and found that CSN occludes both SCF functional sites-the catalytic Rbx1-Cul1 C-terminal domain and the substrate receptor.
View Article and Find Full Text PDFThe 26S proteasome plays a fundamental role in eukaryotic homeostasis by undertaking the highly controlled degradation of a wide range of proteins, including key cellular regulators such as those controlling cell-cycle progression and apoptosis. Here we report the structure of the human 26S proteasome determined by cryo-electron microscopy and single-particle analysis, with secondary structure elements identified both in the 20S proteolytic core region and in the 19S regulatory particle. We have used this information together with crystal structures, homology models, and other biochemical information to construct a molecular model of the complete 26S proteasome.
View Article and Find Full Text PDFThe 26S proteasome proteolyses ubiquitylated proteins and is assembled from a 20S proteolytic core and two 19S regulatory particles (19S-RP). The 19S-RP scaffolding subunits Rpn1 and Rpn2 function to engage ubiquitin receptors. Rpn1 and Rpn2 are characterized by eleven tandem copies of a 35-40 amino acid repeat motif termed the proteasome/cyclosome (PC) repeat.
View Article and Find Full Text PDFThe multi-subunit DNA-dependent protein kinase (DNA-PK), a crucial player in DNA repair by non-homologous end-joining in higher eukaryotes, consists of a catalytic subunit (DNA-PKcs) and the Ku heterodimer. Ku recruits DNA-PKcs to double-strand breaks, where DNA-PK assembles prior to DNA repair. The interaction of DNA-PK with DNA is regulated via autophosphorylation.
View Article and Find Full Text PDFThe anaphase-promoting complex or cyclosome (APC/C) is an unusually large E3 ubiquitin ligase responsible for regulating defined cell cycle transitions. Information on how its 13 constituent proteins are assembled, and how they interact with co-activators, substrates and regulatory proteins is limited. Here, we describe a recombinant expression system that allows the reconstitution of holo APC/C and its sub-complexes that, when combined with electron microscopy, mass spectrometry and docking of crystallographic and homology-derived coordinates, provides a precise definition of the organization and structure of all essential APC/C subunits, resulting in a pseudo-atomic model for 70% of the APC/C.
View Article and Find Full Text PDFThe ubiquitylation of cell-cycle regulatory proteins by the large multimeric anaphase-promoting complex (APC/C) controls sister chromatid segregation and the exit from mitosis. Selection of APC/C targets is achieved through recognition of destruction motifs, predominantly the destruction (D)-box and KEN (Lys-Glu-Asn)-box. Although this process is known to involve a co-activator protein (either Cdc20 or Cdh1) together with core APC/C subunits, the structural basis for substrate recognition and ubiquitylation is not understood.
View Article and Find Full Text PDFWe have used limited trypsin digestion and reactivity with PEG-maleimides (MPEG) to study Ca(2+)-induced conformational changes of IP(3)Rs in their native membrane environment. We found that Ca(2+) decreased the formation of the 95-kDa C-terminal tryptic fragment when detected by an Ab directed at a C-terminal epitope (CT-1) but not with an Ab recognizing a protected intraluminal epitope. This suggests that Ca(2+) induces a conformational change in the IP(3)R that allows trypsin to cleave the C-terminal epitope.
View Article and Find Full Text PDFBackground: We investigated the effects of the signaling molecules, cyclic AMP (cAMP) and protein-kinase C (PKC), on gap junctional intercellular communication (GJIC) between thymic epithelial cells (TEC).
Results: Treatment with 8-Br-cAMP, a cAMP analog; or forskolin, which stimulates cAMP production, resulted in an increase in dye transfer between adjacent TEC, inducing a three-fold enhancement in the mean fluorescence of coupled cells, ascertained by flow cytometry after calcein transfer. These treatments also increased Cx43 mRNA expression, and stimulated Cx43 protein accumulation in regions of intercellular contacts.
Type III secretion systems (T3SSs) mediate bacterial protein translocation into eukaryotic cells, a process essential for virulence of many Gram-negative pathogens. They are composed of a cytoplasmic secretion machinery and a base that bridges both bacterial membranes, into which a hollow, external needle is embedded. When isolated, the latter two parts are termed the 'needle complex'.
View Article and Find Full Text PDFThe covalent attachment of ubiquitin to target proteins influences various cellular processes, including DNA repair, NF-kappaB signalling and cell survival. The most common mode of regulation by ubiquitin-conjugation involves specialized ubiquitin-binding proteins that bind to ubiquitylated proteins and link them to downstream biochemical processes. Unravelling how the ubiquitin-message is recognized is essential because aberrant ubiquitin-mediated signalling contributes to tumour formation.
View Article and Find Full Text PDFThe 26S proteasome plays an essential role in regulating many cellular processes by the degradation of proteins targeted for breakdown by ubiquitin conjugation. The 26S complex is formed from the 20S core, which contains the proteolytic active sites, and 19S regulatory complexes, which bind to the 20S core to activate it and confer specificity for ubiquitinated protein substrates. We have determined the structure of the human 26S proteasome by electron microscopy and single particle analysis.
View Article and Find Full Text PDFC-protein is a major component of skeletal and cardiac muscle thick filaments. Mutations in the gene encoding cardiac C-protein [cardiac myosin binding protein-C (cMyBP-C)] are one of the principal causes of hypertrophic cardiomyopathy. cMyBP-C is a string of globular domains including eight immunoglobulin-like and three fibronectin-like domains termed C0-C10.
View Article and Find Full Text PDFSpecific residues in the putative pore helix, selectivity filter, and S6 transmembrane helix of the inositol 1,4,5-trisphosphate receptor were mutated in order to examine their effects on channel function. Mutation of 5 of 8 highly conserved residues in the pore helix/selectivity filter region inactivated the channel (C2533A, G2541A, G2545A, G2546A, and G2547A). Of the remaining three mutants, C2527A and R2543A were partially active and G2549A behaved like wild type receptor.
View Article and Find Full Text PDFChemokine receptor CCR3 is highly expressed by eosinophils and signals in response to binding of the eotaxin family of chemokines, which are up-regulated in allergic disorders. Consequently, CCR3 blockade is of interest as a possible therapeutic approach for the treatment of allergic disease. We have described previously a bispecific antagonist of CCR1 and CCR3 named UCB35625 that was proposed to interact with the transmembrane residues Tyr-41, Tyr-113, and Glu-287 of CCR1, all of which are conserved in CCR3.
View Article and Find Full Text PDFBackground: Since the first morphological description of the gap junctions use electron microscopy, a considerable number of techniques has been introduced to evaluate gap junction channel functionality, many of which use dye transfer techniques, such as dye injection and fluorescent dye transfer, analyzed by flow cytometry.
Methods: To analyze dye transfer, generally one population of cells is incubated with calcein-AM (0.5 microM) for 30 min at 37 degrees C, and the other population was incubated with the lipophilic dye DiIC(18) (3) (10 microM) for 1 h at 37 degrees C; after incubation, these cells were washed five times with PBS and cocultured for different times, and then the dye transfer was analyzed by flow cytometry.
The chemokine receptor CCR1 and its principal ligand, CCL3/MIP-1alpha, have been implicated in the pathology of several inflammatory diseases including rheumatoid arthritis, multiple sclerosis, and asthma. As such, these molecules are the focus of much research with the ultimate aim of developing novel therapies. We have described previously a non-competitive small molecule antagonist of CCR1 (UCB 35625), which we hypothesized interacted with amino acids located within the receptor transmembrane (TM) helices (Sabroe, I.
View Article and Find Full Text PDFDuring maturation, thymocytes interact directly and indirectly with different cell types of the thymic microenvironment. Such a cellular communication has been basically ascribed to soluble factors and surface receptors. However, little attention has been given to cellular communication mediated by gap junctions.
View Article and Find Full Text PDF