34 results found
Shenoy AR, Furniss RCD, Goddard PJ, et al., 2018, Modulation of Host Cell Processes by T3SS Effectors., Curr Top Microbiol Immunol, ISSN: 0070-217X
Two of the enteric Escherichia coli pathotypes-enteropathogenic E. coli (EPEC) and enterohaemorrhagic E. coli (EHEC)-have a conserved type 3 secretion system which is essential for virulence. The T3SS is used to translocate between 25 and 50 bacterial proteins directly into the host cytosol where they manipulate a variety of host cell processes to establish a successful infection. In this chapter, we discuss effectors from EPEC/EHEC in the context of the host proteins and processes that they target-the actin cytoskeleton, small guanosine triphosphatases and innate immune signalling pathways that regulate inflammation and cell death. Many of these translocated proteins have been extensively characterised, which has helped obtain insights into the mechanisms of pathogenesis of these bacteria and also understand the host pathways they target in more detail. With increasing knowledge of the positive and negative regulation of host signalling pathways by different effectors, a future challenge is to investigate how the specific effector repertoire of each strain cooperates over the course of an infection.
Bist P, Cheong WS, Ng A, et al., 2017, E3 Ubiquitin ligase ZNRF4 negatively regulates NOD2 signalling and induces tolerance to MDP, NATURE COMMUNICATIONS, Vol: 8, ISSN: 2041-1723
Eldridge MJG, Sanchez-Garrido J, Hoben GF, et al., 2017, The Atypical Ubiquitin E2 Conjugase UBE2L3 Is an Indirect Caspase-1 Target and Controls IL-1 beta Secretion by Inflammasomes, CELL REPORTS, Vol: 18, Pages: 1285-1297, ISSN: 2211-1247
Mazon-Moya MJ, Willis AR, Torraca V, et al., 2017, Septins restrict inflammation and protect zebrafish larvae from Shigella infection, PLOS PATHOGENS, Vol: 13, ISSN: 1553-7366
Pallett MA, Crepin VF, Serafini N, et al., 2017, Bacterial virulence factor inhibits caspase-4/11 activation in intestinal epithelial cells, MUCOSAL IMMUNOLOGY, Vol: 10, Pages: 602-612, ISSN: 1933-0219
Thurston TLM, Matthews SA, Jennings E, et al., 2016, Growth inhibition of cytosolic Salmonella by caspase-1 and caspase-11 precedes host cell death, NATURE COMMUNICATIONS, Vol: 7, ISSN: 2041-1723
Eldridge MJG, Shenoy AR, 2015, Antimicrobial inflammasomes: unified signalling against diverse bacterial pathogens, CURRENT OPINION IN MICROBIOLOGY, Vol: 23, Pages: 32-41, ISSN: 1369-5274
Mostowy S, Shenoy AR, 2015, The cytoskeleton in cell-autonomous immunity: structural determinants of host defence, NATURE REVIEWS IMMUNOLOGY, Vol: 15, Pages: 559-573, ISSN: 1474-1733
Surana S, Shenoy AR, Krishnan Y, 2015, Designing DNA nanodevices for compatibility with the immune system of higher organisms, NATURE NANOTECHNOLOGY, Vol: 10, Pages: 741-747, ISSN: 1748-3387
Matsuzawa T, Kim B-H, Shenoy AR, et al., 2012, IFN-γ elicits macrophage autophagy via the p38 MAPK signaling pathway., J Immunol, Vol: 189, Pages: 813-818
Autophagy is a major innate immune defense pathway in both plants and animals. In mammals, this cascade can be elicited by cytokines (IFN-γ) or pattern recognition receptors (TLRs and nucleotide-binding oligomerization domain-like receptors). Many signaling components in TLR- and nucleotide-binding oligomerization domain-like receptor-induced autophagy are now known; however, those involved in activating autophagy via IFN-γ remain to be elucidated. In this study, we engineered macrophages encoding a tandem fluorescently tagged LC3b (tfLC3) autophagosome reporter along with stably integrated short hairpin RNAs to demonstrate IFN-γ-induced autophagy required JAK 1/2, PI3K, and p38 MAPK but not STAT1. Moreover, the autophagy-related guanosine triphosphatase Irgm1 proved dispensable in both stable tfLC3-expressing RAW 264.7 and tfLC3-transduced Irgm1(-/-) primary macrophages, revealing a novel p38 MAPK-dependent, STAT1-independent autophagy pathway that bypasses Irgm1. These unexpected findings have implications for understanding how IFN-γ-induced autophagy is mobilized within macrophages for inflammation and host defense.
Shenoy AR, Wellington DA, Kumar P, et al., 2012, GBP5 Promotes NLRP3 Inflammasome Assembly and Immunity in Mammals, SCIENCE, Vol: 336, Pages: 481-485, ISSN: 0036-8075
Kim B-H, Shenoy AR, Kumar P, et al., 2011, A family of IFN-γ-inducible 65-kD GTPases protects against bacterial infection., Science, Vol: 332, Pages: 717-721
Immune interferon gamma (IFN-γ) is essential for mammalian host defense against intracellular pathogens. IFN-γ induces nearly 2000 host genes, yet few have any assigned function. Here, we examined a complete mouse 65-kilodalton (kD) guanylate-binding protein (Gbp) gene family as part of a 43-member IFN-γ-inducible guanosine triphosphatase (GTPase) superfamily in mouse and human genomes. Family-wide loss-of-function analysis found that at least four Gbps--Gbp1, Gbp6, Gbp7, and Gbp10--conferred cell-autonomous immunity to listerial or mycobacterial infection within macrophages and gene-deficient animals. These Gbps solicited host defense proteins, including the phagocyte oxidase, antimicrobial peptides, and autophagy effectors, to kill intracellular bacteria. Thus, specific 65-kD Gbps coordinate a potent oxidative and vesicular trafficking program to protect the host from infection.
Biswas KH, Shenoy AR, Dutta A, et al., 2009, The Evolution of Guanylyl Cyclases as Multidomain Proteins: Conserved Features of Kinase-Cyclase Domain Fusions, JOURNAL OF MOLECULAR EVOLUTION, Vol: 68, Pages: 587-602, ISSN: 0022-2844
Tyagi R, Shenoy AR, Visweswariah SS, 2009, Characterization of an Evolutionarily Conserved Metallophosphoesterase That Is Expressed in the Fetal Brain and Associated with the WAGR Syndrome, JOURNAL OF BIOLOGICAL CHEMISTRY, Vol: 284, Pages: 5217-5228, ISSN: 0021-9258
Dass BKM, Sharma R, Shenoy AR, et al., 2008, Cyclic AMP in mycobacteria: Characterization and functional role of the rv1647 ortholog in Mycobacterium smegmatis, JOURNAL OF BACTERIOLOGY, Vol: 190, Pages: 3824-3834, ISSN: 0021-9193
Shenoy AR, Capuder M, Draskovic P, et al., 2007, Structural and biochemical analysis of the Rv0805 cyclic nucleotide phosphodiesterase from Mycobacterium tuberculosis, JOURNAL OF MOLECULAR BIOLOGY, Vol: 365, Pages: 211-225, ISSN: 0022-2836
Shenoy AR, Kim B-H, Choi H-P, et al., 2007, Emerging themes in IFN-gamma-induced macrophage immunity by the p47 and p65 GTPase families, IMMUNOBIOLOGY, Vol: 212, Pages: 771-784, ISSN: 0171-2985
Jaleel M, Saha S, Shenoy AR, et al., 2006, The kinase homology domain of receptor guanylyl cyclase C: ATP binding and identification of an adenine nucleotide sensitive site, BIOCHEMISTRY, Vol: 45, Pages: 1888-1898, ISSN: 0006-2960
Ketkar AD, Shenoy AR, Ramagopal UA, et al., 2006, A structural basis for the role of nucleotide specifying residues in regulating the oligomerization of the Rv1625c adenylyl cyclase from M. tuberculosis., J Mol Biol, Vol: 356, Pages: 904-916, ISSN: 0022-2836
The Rv1625c Class III adenylyl cyclase from Mycobacterium tuberculosis is a homodimeric enzyme with two catalytic centers at the dimer interface, and shows sequence similarity with the mammalian adenylyl and guanylyl cyclases. Mutation of the substrate-specifying residues in the catalytic domain of Rv1625c, either independently or together, to those present in guanylyl cyclases not only failed to confer guanylyl cyclase activity to the protein, but also severely abrogated the adenylyl cyclase activity of the enzyme. Biochemical analysis revealed alterations in the behavior of the mutants on ion-exchange chromatography, indicating differences in the surface-exposed charge upon mutation of substrate-specifying residues. The mutant proteins showed alterations in oligomeric status as compared to the wild-type enzyme, and differing abilities to heterodimerize with the wild-type protein. The crystal structure of a mutant has been solved to a resolution of 2.7A. On the basis of the structure, and additional biochemical studies, we provide possible reasons for the altered properties of the mutant proteins, as well as highlight unique structural features of the Rv1625c adenylyl cyclase.
Macario AJL, Brocchieri L, Shenoy AR, et al., 2006, Evolution of a protein-folding machine: Genomic and evolutionary analyses reveal three lineages of the archaeal hsp70(dnaK) gene, JOURNAL OF MOLECULAR EVOLUTION, Vol: 63, Pages: 74-86, ISSN: 0022-2844
Shenoy AR, Visweswariah SS, 2006, New messages from old messengers: cAMP and mycobacteria, TRENDS IN MICROBIOLOGY, Vol: 14, Pages: 543-550, ISSN: 0966-842X
Shenoy AR, Visweswariah SS, 2006, Mycobacterial adenylyl cyclases: Biochemical diversity and structural plasticity, FEBS LETTERS, Vol: 580, Pages: 3344-3352, ISSN: 0014-5793
Shenoy AR, Sreenath N, Podobnik M, et al., 2005, The Rv0805 gene from Mycobacterium tuberculosis encodes a 3 ',5 '-cyclic nucleotide phosphodiesterase: Biochemical and mutational analysis, BIOCHEMISTRY, Vol: 44, Pages: 15695-15704, ISSN: 0006-2960
Shenoy AR, Sreenath NP, Mahalingam M, et al., 2005, Characterization of phylogenetically distant members of the adenylate cyclase family from mycobacteria: Rv1647 from Mycobacterium tuberculosis and its orthologue ML1399 from M. leprae, BIOCHEMICAL JOURNAL, Vol: 387, Pages: 541-551, ISSN: 0264-6021
Shenoy AR, Srinivas A, Mahalingam M, et al., 2005, An adenylyl cyclase pseudogene in Mycobacterium tuberculosis has a functional ortholog in Mycobacterium avium, BIOCHIMIE, Vol: 87, Pages: 557-563, ISSN: 0300-9084
Jaleel M, Shenoy AR, Visweswariah SS, 2004, Tyrphostins are inhibitors of guanylyl and adenylyl cyclases, BIOCHEMISTRY, Vol: 43, Pages: 8247-8255, ISSN: 0006-2960
Ketkar AD, Shenoy AR, Kesavulu MM, et al., 2004, Purification, crystallization and preliminary X-ray diffraction analysis of the catalytic domain of adenylyl cyclase RV1625c from Mycobacterium tuberculosis, ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY, Vol: 60, Pages: 371-373, ISSN: 0907-4449
Shenoy AR, Sivakumar K, Krupa A, et al., 2004, A survey of nucleotide cyclases in actinobacteria: unique domain organization and expansion of the class III cyclase family in Mycobacterium tuberculosis., Comp Funct Genomics, Vol: 5, Pages: 17-38, ISSN: 1531-6912
Cyclic nucleotides are well-known second messengers involved in the regulation of important metabolic pathways or virulence factors. There are six different classes of nucleotide cyclases that can accomplish the task of generating cAMP, and four of these are restricted to the prokaryotes. The role of cAMP has been implicated in the virulence and regulation of secondary metabolites in the phylum Actinobacteria, which contains important pathogens, such as Mycobacterium tuberculosis, M. leprae, M. bovis and Corynebacterium, and industrial organisms from the genus Streptomyces. We have analysed the actinobacterial genome sequences found in current databases for the presence of different classes of nucleotide cyclases, and find that only class III cyclases are present in these organisms. Importantly, prominent members such as M. tuberculosis and M. leprae have 17 and 4 class III cyclases, respectively, encoded in their genomes, some of which display interesting domain fusions seen for the first time. In addition, a pseudogene corresponding to a cyclase from M. avium has been identified as the only cyclase pseudogene in M. tuberculosis and M. bovis. The Corynebacterium and Streptomyces genomes encode only a single adenylyl cyclase each, both of which have corresponding orthologues in M. tuberculosis. A clustering of the cyclase domains in Actinobacteria reveals the presence of typical eukaryote-like, fungi-like and other bacteria-like class III cyclase sequences within this phylum, suggesting that these proteins may have significant roles to play in this important group of organisms.
Shenoy AR, Visweswariah SS, 2004, Class III nucleotide cyclases in bacteria and archaebacteria: lineage-specific expansion of adenylyl cyclases and a dearth of guanylyl cyclases, FEBS LETTERS, Vol: 561, Pages: 11-21, ISSN: 0014-5793
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