Karl J Schreiber

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Human tumor cells frequently exhibit abnormalities in the major histocompatibility complex (MHC) class I surface expression which can be due to structural alterations and/or dysregulation of various components of the MHC class I antigen processing machinery, such as HLA class I heavy and light chains, the peptide transporter and the proteasome subunits.(More)
Gram-negative bacterial pathogens have evolved a number of virulence-promoting strategies including the production of extracellular polysaccharides such as alginate and the injection of effector proteins into host cells. The induction of these virulence mechanisms can be associated with concomitant downregulation of the abundance of proteins that trigger(More)
Successful pathogenesis requires a number of coordinated processes whose genetic bases remain to be fully characterized. We utilized a high-throughput, liquid media-based assay to screen transposon disruptants of the phytopathogen Pseudomonas syringae pv. maculicola ES4326 to identify genes required for virulence on Arabidopsis. Many genes identified(More)
The study of plant pathogenesis and the development of effective treatments to protect plants from diseases could be greatly facilitated by a high-throughput pathosystem to evaluate small-molecule libraries for inhibitors of pathogen virulence. The interaction between the Gram-negative bacterium Pseudomonas syringae and Arabidopsis thaliana is a model for(More)
The hepatitis C virus (HCV) is a growing global health problem. Small molecules that interfere with host-viral interactions can serve as powerful tools for elucidating the molecular mechanisms of pathogenesis and defining new strategies for therapeutic development. Using a cell-based screen involving subgenomic HCV replicons, we identified the ability of 18(More)
Despite the tremendous economic impact of cereal crop pathogens such as the fungus Fusarium graminearum, the development of strategies for enhanced crop protection is hampered by complex host genetics and difficulties in performing high-throughput analyses. To bypass these challenges, we have developed an assay in which the interaction between F.(More)
Plant immunity to coevolved pathogens relies on the perception of pathogenic effectors by nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins-sophisticated intracellular receptors that have both perception and signaling roles in activating defenses. Given the conserved domain architecture of NLRs, a structural biology perspective is(More)
Bacterial pathogens inject type III secreted effector (T3SE) proteins into their hosts where they display dual roles depending on the host genotype. T3SEs promote bacterial virulence in susceptible hosts, and elicit immunity in resistant hosts. T3SEs are typically recognized when they modify a host target that is associated with a NOD-like receptor protein.(More)
Upon recognition of pathogen virulence effectors, plant nucleotide-binding leucine-rich repeat (NLR) proteins induce defense responses including localized host cell death. In an effort to understand the molecular mechanisms leading to this response, we examined the Arabidopsis thaliana NLR protein RECOGNITION OF PERONOSPORA PARASITICA1 (RPP1), which(More)
The self-association of Toll/interleukin-1 receptor/resistance protein (TIR) domains has been implicated in signaling in plant and animal immunity receptors. Structure-based studies identified different TIR-domain dimerization interfaces required for signaling of the plant nucleotide-binding oligomerization domain-like receptors (NLRs) L6 from flax and(More)