The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Augustine M K Choi - One of the best experts on this subject based on the ideXlab platform.
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regulation and function of the nucleotide binding Domain leucine rich repeat containing receptor Pyrin Domain containing 3 inflammasome in lung disease
American Journal of Respiratory Cell and Molecular Biology, 2016Co-Authors: Seonmin Lee, Gee Young Suh, Stefan W Ryter, Augustine M K ChoiAbstract:Inflammasomes are specialized inflammatory signaling platforms that govern the maturation and secretion of proinflammatory cytokines, such as IL-1β and IL-18, through the regulation of caspase-1-dependent proteolytic processing. Several nucleotide binding Domain leucine-rich repeat-containing receptor (NLR) family members (i.e., NLR family, Pyrin Domain containing [NLRP] 1, NLRP3, and NLR family, caspase recruitment Domain containing-4 [NLRC4]) as well as the Pyrin and hemopoietic expression, interferon-inducibility, nuclear localization Domain-containing family member, absent in melanoma 2, can form inflammasome complexes in human cells. In particular, the NLRP3 inflammasome is activated in response to cellular stresses through a two-component pathway, involving Toll-like receptor 4-ligand interaction (priming) followed by a second signal, such as ATP-dependent P2X purinoreceptor 7 receptor activation. Emerging studies suggest that the NLRP3 inflammasome can exert pleiotropic effects in human diseases with potentially both pro- and antipathogenic sequelae. Whereas NLRP3 inflammasome activation can serve as a vital component of host defense against invading bacteria and pathogens, excessive activation of the inflammasome can lead to inflammation-associated tissue injury in the setting of chronic disease. In addition, pyroptosis, an inflammasome-associated mode of cell death, contributes to host defense. Recent research has described the regulation and function of the NLRP3 inflammasome in various pulmonary diseases, including acute lung injury and acute respiratory distress syndrome, sepsis, respiratory infections, chronic obstructive pulmonary disease, asthma, pulmonary hypertension, cystic fibrosis, and idiopathic pulmonary fibrosis. The NLRP3 and related inflammasomes, and their regulated cytokines or receptors, may represent novel diagnostic or therapeutic targets in pulmonary diseases and other diseases in which inflammation contributes to pathogenesis.
Matthias Geyer - One of the best experts on this subject based on the ideXlab platform.
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crystal structure of the human nlrp9 Pyrin Domain suggests a distinct mode of inflammasome assembly
FEBS Letters, 2020Co-Authors: Michael Marleaux, Kanchan Anand, Eicke Latz, Matthias GeyerAbstract:Inflammasomes are cytosolic multimeric signaling complexes of the innate immune system that induce activation of caspases. The NOD-like receptor NLRP9 recruits the adaptor protein ASC to form an ASC-dependent inflammasome to limit rotaviral replication in intestinal epithelial cells, but only little is known about the molecular mechanisms regulating and driving its assembly. Here, we present the crystal structure of the human NLRP9 Pyrin Domain (PYD). We show that NLRP9PYD is not able to self-polymerize nor to nucleate ASC specks in HEK293T cells. A comparison with filament-forming PYDs revealed that NLRP9PYD adopts a conformation compatible with filament formation, but several charge inversions of interfacing residues might cause repulsive effects that prohibit self-oligomerization. These results propose that inflammasome assembly of NLRP9 might differ largely from what we know of other inflammasomes.
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nlrp3 inflammasome assembly is regulated by phosphorylation of the Pyrin Domain
Journal of Experimental Medicine, 2017Co-Authors: Andrea Stutz, Carlchristian Kolbe, Rainer Stahl, Gabor Horvath, Bernardo S Franklin, Olivia Van Ray, Rebecca Brinkschulte, Matthias GeyerAbstract:NLRP3 is a cytosolic pattern recognition receptor that senses microbes and endogenous danger signals. Upon activation, NLRP3 forms an inflammasome with the adapter ASC, resulting in caspase-1 activation, release of proinflammatory cytokines and cell death. How NLRP3 activation is regulated by transcriptional and posttranslational mechanisms to prevent aberrant activation remains incompletely understood. Here, we identify three conserved phosphorylation sites in NLRP3 and demonstrate that NLRP3 activation is controlled by phosphorylation of its Pyrin Domain (PYD). Phosphomimetic residues in NLRP3 PYD abrogate inflammasome activation and structural modeling indicates that phosphorylation of the PYD regulates charge-charge interaction between two PYDs that are essential for NLRP3 activation. Phosphatase 2A (PP2A) inhibition or knock-down drastically reduces NLRP3 activation, showing that PP2A can license inflammasome assembly via dephosphorylating NLRP3 PYD. These results propose that the balance between kinases and phosphatases acting on the NLRP3 PYD is critical for NLRP3 activation.
Clarissa Eibl - One of the best experts on this subject based on the ideXlab platform.
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intrinsic flexibility of nlrp Pyrin Domains is a key factor in their conformational dynamics fold stability and dimerization
Protein Science, 2015Co-Authors: Clarissa Eibl, Roland G Huber, Julian E FuchsAbstract:Nucleotide-binding Domain leucine-rich repeat-containing receptors (NLRs) are key proteins in the innate immune system. The 14 members of the NLRP family of NLRs contain an N-terminal Pyrin Domain which is central for complex formation and signal transduction. Recently, X-ray structures of NLRP14 revealed an unexpected rearrangement of the α5/6 stem-helix of the Pyrin Domain allowing a novel symmetric dimerization mode. We characterize the conformational transitions underlying NLRP oligomerization using molecular dynamics simulations. We describe conformational stability of native NLRP14 and mutants in their monomeric and dimeric states and compare them to NLRP4, a representative of a native Pyrin Domain fold. Thereby, we characterize the interplay of conformational dynamics, fold stability, and dimerization in NLRP Pyrin Domains. We show that intrinsic flexibility of NLRP Pyrin Domains is a key factor influencing their behavior in physiological conditions. Additionally, we provide further evidence for the crucial importance of a charge relay system within NLRPs that critically influences their conformational ensemble in solution.
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Structures of the NLRP14 Pyrin Domain reveal a conformational switch mechanism regulating its molecular interactions.
Acta crystallographica. Section D Biological crystallography, 2014Co-Authors: Clarissa Eibl, Manuel Hessenberger, Julia Wenger, Hans BrandstetterAbstract:The cytosolic tripartite NLR receptors serve as important signalling platforms in innate immunity. While the C-terminal Domains act as sensor and activation modules, the N-terminal death-like Domain, e.g. the CARD or Pyrin Domain, is thought to recruit downstream effector molecules by homotypic interactions. Such homotypic complexes have been determined for all members of the death-Domain superfamily except for Pyrin Domains. Here, crystal structures of human NLRP14 Pyrin-Domain variants are reported. The wild-type protein as well as the clinical D86V mutant reveal an unexpected rearrangement of the C-terminal helix α6, resulting in an extended α5/6 stem-helix. This reordering mediates a novel symmetric Pyrin-Domain dimerization mode. The conformational switching is controlled by a charge-relay system with a drastic impact on protein stability. How the identified charge relay allows classification of NLRP receptors with respect to distinct recruitment mechanisms is discussed.
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structural and functional analysis of the nlrp4 Pyrin Domain
Biochemistry, 2012Co-Authors: Clarissa Eibl, Anderson S Pinheiro, Martina Proell, Manuel Hessenberger, Julia Wenger, Simina Grigoriu, Sandra Puehringer, Roland N Wagner, John C Reed, Rebecca PageAbstract:NLRP4 is a member of the nucleotide-binding and leucine-rich repeat receptor (NLR) family of cytosolic receptors and a member of an inflammation signaling cascade. Here, we present the crystal structure of the NLRP4 Pyrin Domain (PYD) at 2.3 A resolution. The NLRP4 PYD is a member of the death Domain (DD) superfamily and adopts a DD fold consisting of six α-helices tightly packed around a hydrophobic core, with a highly charged surface that is typical of PYDs. Importantly, however, we identified several differ- ences between the NLRP4 PYD crystal structure and other PYD structures that are significant enough to affect NLRP4 function and its interactions with binding partners. Notably, the length of helix α3 and the α2−α3 connecting loop in the NLRP4 PYD are unique among PYDs. The apoptosis-associated speck-like protein containing a CARD (ASC) is an adaptor protein whose interactions with a number of distinct PYDs are believed to be critical for activation of the inflammatory response. Here, we use co-immunoprecipitation, yeast two-hybrid, and nuclear magnetic resonance chemical shift perturbation analysis to demonstrate that, despite being important for activation of the inflammatory response and sharing several similarities with other known ASC-interacting PYDs (i.e., ASC2), NLRP4 does not interact with the adaptor protein ASC. Thus, we propose that the factors governing homotypic PYD interactions are more complex than the currently accepted model, which states that complementary charged surfaces are the main determinants of PYD−PYD interaction specificity.
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The NLRP12 Pyrin Domain: structure, dynamics, and functional insights
Journal of Molecular Biology, 2011Co-Authors: Anderson S Pinheiro, Clarissa Eibl, Robert Schwarzenbacher, Zeynep Ekman-vural, Wolfgang PetiAbstract:The initial line of defense against infection is sustained by the innate immune system. Together, membrane-bound Toll-like receptors and cytosolic nucleotide-binding Domain and leucine-rich repeat-containing receptors (NLR) play key roles in the innate immune response by detecting bacterial and viral invaders as well as endogenous stress signals. NLRs are multi-Domain proteins with varying N-terminal effector Domains that are responsible for regulating downstream signaling events. Here, we report the structure and dynamics of the N-terminal Pyrin Domain of NLRP12 (NLRP12 PYD) determined using NMR spectroscopy. NLRP12 is a non-inflammasome NLR that has been implicated in the regulation of Toll-like receptor-dependent nuclear factor-κB activation. NLRP12 PYD adopts a typical six-helical bundle death Domain fold. By direct comparison with other PYD structures, we identified hydrophobic residues that are essential for the stable fold of the NLRP PYD family. In addition, we report the first in vitro confirmed non-homotypic PYD interaction between NLRP12 PYD and the pro-apoptotic protein Fas-associated factor 1 (FAF-1), which links the innate immune system to apoptotic signaling. Interestingly, all residues that participate in this protein:protein interaction are confined to the α2-α3 surface, a region of NLRP12 PYD that differs most between currently reported NLRP PYD structures. Finally, we experimentally highlight a significant role for tryptophan 45 in the interaction between NLRP12 PYD and the FAF-1 UBA Domain.
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three dimensional structure of the nlrp7 Pyrin Domain insight into Pyrin Pyrin mediated effector Domain signaling in innate immunity
Journal of Biological Chemistry, 2010Co-Authors: Anderson S Pinheiro, Clarissa Eibl, Rebecca Page, Martina Proell, Robert Schwarzenbacher, Wolfgang PetiAbstract:The innate immune system provides an initial line of defense against infection. Nucleotide-binding Domain- and leucine-rich repeat-containing protein (NLR or (NOD-like)) receptors play a critical role in the innate immune response by surveying the cytoplasm for traces of intracellular invaders and endogenous stress signals. NLRs themselves are multi-Domain proteins. Their N-terminal effector Domains (typically a Pyrin or caspase activation and recruitment Domain) are responsible for driving downstream signaling and initiating the formation of inflammasomes, multi-component complexes necessary for cytokine activation. However, the currently available structures of NLR effector Domains have not yet revealed the mechanism of their differential modes of interaction. Here, we report the structure and dynamics of the N-terminal Pyrin Domain of NLRP7 (NLRP7 PYD) obtained by NMR spectroscopy. The NLRP7 PYD adopts a six-α-helix bundle death Domain fold. A comparison of conformational and dynamics features of the NLRP7 PYD with other PYDs showed distinct differences for helix α3 and loop α2-α3, which, in NLRP7, is stabilized by a strong hydrophobic cluster. Moreover, the NLRP7 and NLRP1 PYDs have different electrostatic surfaces. This is significant, because death Domain signaling is driven by electrostatic contacts and stabilized by hydrophobic interactions. Thus, these results provide new insights into NLRP signaling and provide a first molecular understanding of inflammasome formation.
Gottfried Otting - One of the best experts on this subject based on the ideXlab platform.
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role of charged and hydrophobic residues in the oligomerization of the Pyrin Domain of asc
Biochemistry, 2005Co-Authors: Mie Moriya, Edvards Liepinsh, Gottfried Otting, Shunichiro Taniguchi, Junji SagaraAbstract:Apoptosis-associated speck-like protein containing a caspase recruitment Domain (ASC) is an adaptor protein composed of two homophilic protein-protein interaction Domains, a Pyrin Domain (PYD) and a caspase recruitment Domain. PYD-dependent oligomerization of ASC is thought to play a crucial role in formation of a molecular platform, the inflammasome, which activates caspase-1. When expressed in cells, the PYD of ASC was shown to form cytoplasmic filaments through self-association. Over 70 single point mutants were analyzed for filament formation in cells expressing the mutant proteins. The set of mutations comprised every single amino acid residue with a charged side chain (Arg, Lys, Asp, and Glu) and a large hydrophobic side chain (Ile, Leu, Met, Phe, Pro, and Val). Filament formation of the ASC PYD was prevented by mutation of Lys21, Leu25, Lys26, Pro40, Arg41, Asp48, and Asp51 of helices 2, 3, and 4. These data identify a coherent interaction surface, establishing a molecular model of PYD-PYD complexes with an important role for charge-charge interactions.
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the death Domain fold of the asc Pyrin Domain presenting a basis for Pyrin Pyrin recognition
Journal of Molecular Biology, 2003Co-Authors: Edvards Liepinsh, Raitis Barbals, Edgar Dahl, Anatoly Sharipo, Eike Staub, Gottfried OttingAbstract:The Pyrin Domain is a conserved sequence motif identified in more than 20 human proteins with putative functions in apoptotic and inflammatory signalling pathways. The three-dimensional structure of the Pyrin Domain from human ASC was determined by NMR spectroscopy. The structure determination reveals close structural similarity to death Domains, death effector Domains, and caspase activation and recruitment Domains, although the structural alignment with these other members of the death-Domain superfamily differs from previously predicted amino acid sequence alignments. Two highly positively and negatively charged surfaces in the Pyrin Domain of ASC result in a strong electrostatic dipole moment that is predicted to be present also in related Pyrin Domains. These results suggest that electrostatic interactions play an important role for the binding between Pyrin Domains. Consequently, the previously reported binding between the Pyrin Domains of ASC and ASC2/POP1 or between the zebrafish Pyrin Domains of zAsc and Caspy is proposed to involve interactions between helices 2 and 3 of one Pyrin Domain with helices 1 and 4 of the other Pyrin Domain, in analogy to previously reported homophilic interactions between caspase activation and recruitment Domains.
Giamila Fantuzzi - One of the best experts on this subject based on the ideXlab platform.
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inhibition of the nucleotide binding Domain leucine rich containing family Pyrin Domain containing 3 inflammasome reduces the severity of experimentally induced acute pancreatitis in obese mice
Translational Research, 2014Co-Authors: Jason York, Karla J Castellanos, Robert J Cabay, Giamila FantuzziAbstract:Acute pancreatitis (AP), although most often a mild and self-limiting inflammatory disease, worsens to a characteristically necrotic severe acute pancreatitis (SAP) in about 20% of cases. Obesity, affecting more than one-third of American adults, is a risk factor for the development of SAP, but the exact mechanism of this association has not been identified. Coincidental with chronic low-grade inflammation, activation of the nucleotide-binding Domain, leucine-rich containing family, Pyrin-Domain containing 3 (NLRP3) inflammasome increases with obesity. Lean mice genetically deficient in specific components of the NLRP3 inflammasome are protected from experimentally induced AP, indicating a direct involvement of this pathway in AP pathophysiology. We hypothesized that inhibition of the NLRP3 inflammasome with the sulfonylurea drug glyburide would reduce disease severity in obese mice with cerulein-induced SAP. Treatment with glyburide led to significantly reduced relative pancreatic mass and water content and less pancreatic damage and cell death in genetically obese ob/ob mice with SAP compared with vehicle-treated obese SAP mice. Glyburide administration in ob/ob mice with cerulein-induced SAP also resulted in significantly reduced serum levels of interleukin 6, lipase, and amylase and led to lower production of lipopolysaccharide-stimulated interleukin 1β release in cultured peritoneal cells, compared with vehicle-treated ob/ob mice with SAP. Together, these data indicate involvement of the NLRP3 inflammasome in obesity-associated SAP and expose the possible utility of its inhibition in prevention or treatment of SAP in obese individuals.
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featured new investigator inhibition of the nucleotide binding Domain leucine rich containing family Pyrin Domain containing 3 inflammasome reduces the severity of experimentally induced acute pancreatitis in obese mice
2014Co-Authors: Jason York, Karla J Castellanos, Robert J Cabay, Giamila FantuzziAbstract:Acute pancreatitis (AP), although most often a mild and self-limiting inflammatory disease, worsens to a characteristically necrotic severe acute pancreatitis (SAP) in about 20% of cases. Obesity, affecting more than one-third of American adults, is a risk factor for the development of SAP, but the exact mechanism of this association has not been identified. Coincidental with chronic low-grade inflammation, activation of the nucleotide-binding Domain, leucine-rich containing family, Pyrin-Domain containing 3 (NLRP3) inflammasome increases with obesity. Lean mice genetically deficient in specific components of the NLRP3 inflammasome are protected from experimentally induced AP, indicating a direct involvement of this pathway in AP pathophysiology. We hypothesized that inhibition of the NLRP3 inflammasome with the sulfonylurea drug glyburide would reduce disease severity in obese mice with cerulein-induced SAP. Treatment with glyburide led to significantly reduced relative pancreatic mass and water content and less pancreatic damage and cell death in genetically obese ob/ob mice with SAP compared with vehicle-treated obese SAP mice. Glyburide administration in ob/ob mice with cerulein-induced SAP also resulted in significantly reduced serum levels of interleukin 6, lipase, and amylase and led to lower production of lipopolysaccharide-stimulated interleukin 1b release in cultured peritoneal cells, compared with vehicle-treated ob/ob mice with SAP. Together, these data indicate involvement of the NLRP3 inflammasome in obesityassociated SAP and expose the possible utility of its inhibition in prevention or treatment of SAP in obese individuals. (Translational Research 2014;164:259‐269)
