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Cellular immunity against viral infection and tumour cells depends on antigen presentation by major histocompatibility complex class I (MHC I) molecules. Intracellular antigenic peptides are transported into the endoplasmic reticulum by the transporter associated with antigen processing (TAP) and then loaded onto the nascent MHC I molecules, which are exported to the cell surface and present peptides to the immune system (1). Cytotoxic T lymphocytes recognize non-self peptides and program the infected or malignant cells for apoptosis. Defects in TAP account for immunodeficiency and tumour development. To escape immune surveillance, some viruses have evolved strategies either to downregulate TAP expression or directly inhibit TAP activity. So far, neither the architecture of TAP nor the mechanism of viral inhibition has been elucidated at the structural level. Here we describe the cryo-electron microscopy structure of human TAP in complex with its inhibitor ICP47, a small protein produced by the herpes simplex virus I. Here we show that the 12 transmembrane helices and 2 cytosolic nucleotide-binding domains of the transporter adopt an inward-facing conformation with the two nucleotide-binding domains separated. The viral inhibitor ICP47 forms a long helical hairpin, which plugs the translocation pathway of TAP from the cytoplasmic side. Association of ICP47 precludes substrate binding and prevents nucleotide-binding domain closure necessary for ATP hydrolysis. This work illustrates a striking example of immune evasion by persistent viruses. By blocking viral antigens from entering the endoplasmic reticulum, herpes simplex virus is hidden from cytotoxic T lymphocytes, which may contribute to establishing a lifelong infection in the host., Inside our body, every nucleated cell has surface 'barcodes' that are surveyed by the immune system. These barcodes are peptides derived from intracellular proteins, presented on the surface by MHC [...]

Author(s): Jan H. Lui [1]; Tomasz J. Nowakowski [1]; Alex A. Pollen [1]; Ashkan Javaherian [1]; Arnold R. Kriegstein (corresponding author) [1]; Michael C. Oldham (corresponding author) [1] Evolutionary expansion [...]

Autosomal dominant mutations of the RNA/DNA binding protein FUS are linked to familial amyotrophic lateral sclerosis (FALS); however, it is not clear how FUS mutations cause neurodegeneration. Using transgenic mice expressing a common FALS-associated FUS mutation (FUS-R521C mice), we found that mutant FUS proteins formed a stable complex with WT FUS proteins and interfered with the normal interactions between FUS and histone deacetylase 1 (HDAC1). Consequently, FUS-R521C mice exhibited evidence of DNA damage as well as profound dendritic and synaptic phenotypes in brain and spinal cord. To provide insights into these defects, we screened neural genes for nucleotide oxidation and identified brain-derived neurotrophic factor (Bdnf ) as a target of FUS-R521C--associated DNA damage and RNA splicing defects in mice. Compared with WT FUS, mutant FUS-R521C proteins formed a more stable complex with Bdnf RNA in electrophoretic mobility shift assays. Stabilization of the FUS/Bdnf RNA complex contributed to Bdnf splicing defects and impaired BDNF signaling through receptor TrkB. Exogenous BDNF only partially restored dendrite phenotype in FUS-R521C neurons, suggesting that BDNF-independent mechanisms may contribute to the defects in these neurons. Indeed, RNA-seq analyses of FUS-R521C spinal cords revealed additional transcription and splicing defects in genes that regulate dendritic growth and synaptic functions. Together, our results provide insight into how gain-of-function FUS mutations affect critical neuronal functions., Introduction Autosomal dominant mutations in RNA/DNA binding protein fused in sarcoma/translocated in liposarcoma (FUS/TLS) have been causally linked to familial ALS (FALS). The main pathological features in FALS with FUS [...]

Author(s): Shawn F. Sorrells [1, 2]; Mercedes F. Paredes [1, 3]; Arantxa Cebrian-Silla [4]; Kadellyn Sandoval [1, 3]; Dashi Qi [5]; Kevin W. Kelley [1]; David James [1]; Simone Mayer [...]

Efficient carbon utilization is critical to the survival of microorganisms in competitive environments. To optimize energy usage, bacteria have developed an integrated control system to preferentially uptake carbohydrates that support rapid growth. The availability of a preferred carbon source, such as glucose, represses the synthesis and activities of proteins necessary for the transport and metabolism of secondary carbon sources. This regulatory phenomenon is defined as carbon catabolite repression1. In enteric bacteria, the key player of carbon catabolite repression is a component of the glucose-specific phosphotransferase system, enzyme IIA ([EIIA.sup.Glc]) (1,2). It is known that unphosphorylated [EIIA.sup.Glc] binds to and inhibits a variety of transporters when glucose is available (1,2). However, understanding the underlying molecular mechanism has been hindered by the complete absence of structures for any [EIIA.sup.Glc]--transporter complexes. Here we present the 3.9 Å crystal structure of Escherichia coli [EIIA.sup.Glc] in complex with the maltose transporter, an ATP-binding cassette (ABC) transporter. The structure shows that two [EIIA.sup.Glc] molecules bind to the cytoplasmic ATPase subunits, stabilizing the transporter in an inward-facing conformation and preventing the structural rearrangements necessary for ATP hydrolysis. We also show that the half-maximal inhibitory concentrations of the full-length [EIIA.sup.Glc] and an amino-terminal truncation mutant differ by 60-fold, consistent with the hypothesis that the amino-terminal region, disordered in the crystal structure, functions as a membrane anchor to increase the effective [EIIA.sup.Glc] concentration at the membrane (3,4). Together these data suggest a model of how the central regulatory protein [EIIA.sup.Glc] allosterically inhibits maltose uptake in E. coli., Carbon catabolite repression (CCR) is common in bacteria and higher organisms: up to 5-10% of all bacterial genes are subject to CCR regulation (1). Different organisms use different pathways to [...]

P-glycoprotein (P-gp) is an ATP-binding cassette transporter that confers multidrug resistance in cancer cells (1,2). It also affects the absorption, distribution and clearance of cancer-unrelated drugs and xenobiotics. For these [...]

ATP-binding cassette (ABC) transporters are powered by a nucleotide-binding domain dimer that opens and closes during cycles of ATP hydrolysis. These domains consist of a RecA-like subdomain and an [alpha]-helical subdomain that is specific to the family. Many studies on isolated domains suggest that the helical subdomain rotates toward the RecA-like subdomain in response to ATP binding, moving the family signature motif into a favorable position to interact with the nucleotide across the dimer interface. Moreover, the transmembrane domains are docked into a cleft at the interface between these subdomains, suggesting a putative role of the rotation in interdomain communication. Electron paramagnetic resonance spectroscopy was used to study the dynamics of this rotation in the intact Escherichia coil maltose transporter [MalFGK.sub.2]. This importer requires a periplasmic maltose-binding protein (MBP) that activates ATP hydrolysis by promoting the closure of the cassette dimer ([MalK.sub.2]). Whereas this rotation occurred during the transport cycle, it required not only trinucleotide, but also MBP, suggesting it is part of a global conformational change in the transporter. Interaction of AMP-PNP-[Mg.sup.2+] and a MBP that is locked in a closed conformation induced a transition from open [MalK.sub.2] to semiopen [MalK.sub.2] without significant subdomain rotation. Inward rotation of the helical subdomain and complete closure of [MalK.sub.2] therefore appear to be coupled to the reorientation of transmembrane helices and the opening of MBP, events that promote transfer of maltose into the transporter. After ATP hydrolysis, the helical subdomain rotates out as [MalK.sub.2] opens, resetting the transporter in an inward-facing conformation. EPR spectroscopy | transport mechanism | membrane protein doi/ 10.1073/pnas.1006544107

ABSTRACT. The purpose of this review is to survey the floristic, ecological and historical research about the Erie Islands and its flora since 1976 and to describe efforts to conserve [...]

FOXP2, the transcriptional factor genes in human brain is identified using chromatin immunoprecipitation followed by microarray analysis (ChIP-chip). The FOXP2-target genes give insights on the vital functions and pathways to explore the genetic basis of human speech and language.

Author(s): Michael L. Oldham [1]; Dheeraj Khare [1]; Florante A. Quiocho [3]; Amy L. Davidson [2]; Jue Chen (corresponding author) [1] ATP-binding cassette (ABC) transporters are ubiquitous membrane protein complexes [...]

The maltose uptake system of Escherichia coli is a well-characterized member of the ATP-binding cassette transporter superfamily. Here we present the 2.8-Å crystal structure of the intact maltose transporter in [...]

The article discusses strength-based case management (SBCM), one of the effective methods of intervention for high-risk youth for negative life outcome. SBCM aims to assist individual in identifying and achieving personal goals.

Comparisons of gene expression between human and non-human primate brains have identified hundreds of differentially expressed genes, yet translating these lists into key functional distinctions between species has proved difficult. Here we provide a more integrated view of human brain evolution by examining the large-scale organization of gene coexpression networks in human and chimpanzee brains. We identify modules of coexpressed genes that correspond to discrete brain regions and quantify their conservation between the species. Module conservation in cerebral cortex is significantly weaker than module conservation in sub-cortical brain regions, revealing a striking gradient that parallels known evolutionary hierarchies. We introduce a method for identifying species-specific network connections and demonstrate how differential network connectivity can be used to identify key drivers of evolutionary change. By integrating our results with comparative genomic sequence data and estimates of protein sequence divergence rates, we confirm a number of network predictions and validate these findings. Our results provide insights into the molecular bases of primate brain organization and demonstrate the general utility of weighted gene coexpression network analysis. microarray | differential network analysis | selection | systems biology

Habitual marijuana smoking is associated with inflammation and atypia of airway epithelium accompanied by symptoms of chronic bronchitis. We hypothesized that [[DELTA].sup.9]-tetrahydrocannabinol (THC), the primary psychoactive component of marijuana, might contribute to these findings by impairing cellular energetics and mitochondrial function. To test this hypothesis, we examined particulate smoke extracts from marijuana cigarettes, tobacco cigarettes, and placebo marijuana (0% THC) cigarettes for their effects on the mitochondrial function of A549 cells in vitro. Only extracts prepared from marijuana cigarettes altered mitochondrial staining by the potentiometric probe JC-1. With the use of a cross-flow, nose-only inhalation system, rats were then exposed for 20 min to whole marijuana smoke and examined for its effects on airway epithelial cells. Inhalation of marijuana smoke produced lung tissue concentrations of THC that were 8-10 times higher than those measured in blood (75 [+ or -] 38 ng/g wet wt tissue vs. 9.2 [+ or -] 2.0 ng/ml), suggesting high local exposure, Intratracheal infusion of JC-1 immediately following marijuana smoke exposure revealed a diffuse decrease in lung cell JC-1 red fluorescence compared with tissue from unexposed or placebo smoke-exposed rats. Exposure to marijuana smoke in vivo also decreased JC-1 red fluorescence (54% decrease, P < 0.01) and ATP levels (75% decrease, P < 0.01) in single-cell preparations of tracheal epithelial cells. These results suggest that inhalation of marijuana smoke has deleterious effects on airway epithelial cell energetics that may contribute to the adverse pulmonary consequences of marijuana smoking. [[DELTA.]sup.9]-tetrahydrocannabinol; JC-l; A549: adenosine 5'-triphosphate

ABSTRACT The goal of this study was to test the following hypotheses: (1) exposure to mobile emissions from mobile sources close to a heavily trafficked roadway will exacerbate airway inflammation [...]

8R-Lipoxygenase and allene oxide synthase (AOS) are parts of a naturally occurring fusion protein from the coral Plexaura homomalla. AOS catalyses the production of an unstable epoxide (an allene oxide) from the fatty acid hydroperoxide generated by the lipoxygenase activity. Here, we report the structure of the AOS domain and its striking structural homology to catalase. Whereas nominal sequence identity between the enzymes had been previously described, the extent of structural homology observed was not anticipated, given that this enzyme activity had been exclusively associated with the P450 superfamily, and conservation of a catalase fold without catalase activity is unprecedented. Whereas the heme environment is largely conserved, the AOS heme is planar and the distal histidine is flanked by two hydrogen-bonding residues. These critical differences likely facilitate the switch from a catalatic activity to that of a fatty acid hydroperoxidase. eicosanoids | heme

Nutrient cycling has been studied on the landscape scale at the Bosque del Apache National Wildlife Refuge, New Mexico, with focus on the role of diel foraging migrations by geese. To test the hypothesis that daily feeding migrations by geese are a significant source of nutrients to wetland systems at the refuge in the Rio Grande River valley, investigation was carried out using biosassays of phytoplankton growth, a combination of mass balance and time budget models for birds, and stable isotope methods to trace the source of nitrogen to food webs. Nitraogen was found to be limiting to primary production by algae in ponds. Fish and crayfish from ponds much used by birds had very low stable nitrogen signatures vs those from the river. Wetland ponds were efficient in keeping the birdborne, allochthonous nutrient load. Only limited amounts of the total phosphorus or nitrogen went downstream.

Records of amphibians and reptiles from the island region of western Lake Erie (Essex County, Ontario; Erie and Ottawa counties, Ohio) span more than a century and include 50 species, 35 of which have been recorded from at least one of 19 islands. Local colonization events, transient species, population declines and local extirpations occurring within this century are evident from these records. Furthermore, these records provide a baseline for monitoring future changes in distribution. Unusual components of the Lake Erie amphibian and reptile fauna include unisexual, polyploid and hybrid ambystomatid salamanders; a population of redback salamanders (Plethodon cinereus) consisting almost entirely of lead-back morphs; populations of Lake Erie water snakes (Nerodia sipedon insularum) that are highly variable in color pattern and provide an exceptionally clear example of the effects of natural selection and gene flow, and populations of common garter snakes (Thamnophis sirtalis) consisting of up to 50% jet-black melanistic individuals. Total number of amphibian and reptile species is positively correlated with island area but uncorrelated with distance to the mainland; however, among salamanders, species numbers decrease with increasing distance to the mainland., INTRODUCTION The island region of western Lake Erie includes taxa and biological communities not found elsewhere and thus makes a unique contribution to the biota of Ohio and Ontario (Clapp, [...]

The planning and design of the Hythe Marina Village located in Southampton, UK, is described. This particular land development effort focused on the importance of maintaining the water availability in such a way that all houses within the area have access to the sea. The area has tightly integrated commercial, residential and recreational components which have been made possible through a high degree of cooperation between the public and private sectors.

The structure of the homodimeric state of the Prp19 U-box is determined by X-ray crystallography and it is shown that the U-box domain of Prp19 exists as a dimer within the context of the Prp19 tetramer. The comparison of the Prp19 U-box homodimer with the heterodimeric complex of BRCA1/ BARD1 RING-finger domains shows a common architecture for a family of oligomeric U-box and RING-finder E3 ubiquitin ligases.