Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.22.36 (caspase-1)
6,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The PYRIN and CARD domains are members of the six-helix bundle death domain-fold superfamily that mediates assembly of large signaling complexes in the apoptotic and inflammatory signaling pathways. Here we show that the PYRIN-CARD protein ASC functions as a caspase-1-activating adaptor. ASC interacted specifically with procaspase-1 via CARD-CARD interactions and induced its oligomerization. Consistent with these results ectopic expression of full-length ASC, but not its isolated CARD or PYRIN domain, with procaspase-1 induced activation of procaspase-1 and processing of pro-interleukin-1beta in transfected cells. Substitution of the PYRIN domain of ASC with an inducible FKBP12 oligomerization domain produced a molecule that can induce caspase-1 activation in response to stimulation with the oligomerization drug AP20187, suggesting that the PYRIN domain functions as an oligomerization domain, whereas the CARD domain functions as the effector domain in the caspase-1 activation pathway. Furthermore stable expression of an isolated CARD of ASC in THP-1 cells diminished interleukin-1beta generation in response to pro-inflammatory cytokines. These results indicate that ASC is involved in the caspase-1 signaling pathway by mediating the assembly of a caspase-1-inflammasome signaling complex in response to pro-inflammatory cytokine stimulation.
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PMID:The PYRIN-CARD protein ASC is an activating adaptor for caspase-1. 1196 58

PYRIN-containing Apaf1-like proteins (PYPAFs) are members of the nucleotide-binding site/leucine-rich repeat (NBS/LRR) family of signal transduction proteins. We report here that PYPAF7 is a novel PYPAF protein that activates inflammatory signaling pathways. The expression of PYPAF7 is highly restricted to immune cells, and its gene maps to chromosome 19q13.4, a locus that contains a cluster of genes encoding numerous PYPAF family members. Co-expression of PYPAF7 with ASC results in the recruitment of PYPAF7 to distinct cytoplasmic loci and a potent synergistic activation of NF-kappa B. To identify other proteins involved in PYPAF7 and ASC signaling pathways, we performed a mammalian two-hybrid screen and identified pro-caspase-1 as a binding partner of ASC. Co-expression of PYPAF7 and ASC results in the synergistic activation of caspase-1 and a corresponding increase in secretion of interleukin-1 beta. In addition, PYPAF1 induces caspase-1-dependent cytokine processing when co-expressed with ASC. These findings indicate that PYPAF family members participate in inflammatory signaling by regulating the activation of NF-kappa B and cytokine processing.
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PMID:PYPAF7, a novel PYRIN-containing Apaf1-like protein that regulates activation of NF-kappa B and caspase-1-dependent cytokine processing. 1201 69

Generation of Interleukin (IL)-1beta via cleavage of its proform requires the activity of caspase-1 (and caspase-11 in mice), but the mechanism involved in the activation of the proinflammatory caspases remains elusive. Here we report the identification of a caspase-activating complex that we call the inflammasome. The inflammasome comprises caspase-1, caspase-5, Pycard/Asc, and NALP1, a Pyrin domain-containing protein sharing structural homology with NODs. Using a cell-free system, we show that proinflammatory caspase activation and proIL-1beta processing is lost upon prior immunodepletion of Pycard. Moreover, expression of a dominant-negative form of Pycard in differentiated THP-1 cells blocks proIL-1beta maturation and activation of inflammatory caspases induced by LPS in vivo. Thus, the inflammasome constitutes an important arm of the innate immunity.
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PMID:The inflammasome: a molecular platform triggering activation of inflammatory caspases and processing of proIL-beta. 2885 14

The genetic bases for several human autoinflammatory syndromes have recently been identified, and the mutated proteins responsible for these diseases are rapidly being characterized. Here, we examine two of these newly identified proteins, pyrin (also called marenostrin, product of the familial Mediterranean fever locus, MEFV) and cryopyrin (product of the CAIS1 locus, and mutated in familial cold urticaria, Muckle Wells syndrome and chronic infantile neurological cutaneous and articular syndrome). Both pyrin and cryopyrin contain an N-terminal domain that encodes a death domain-related structure, now known as the pyrin domain, or PyD. We trace the molecular interactions mediated by these PyDs, examine the evolution of the family of molecules containing this domain, and discuss the function of PyD-containing proteins and their homologues. Synthesis of the available data indicates that both pyrin and cryopyrin interact via their PyDs with a common adaptor protein, ASC. ASC itself participates in at least three important cellular processes: apoptosis, recruitment and activation of pro-caspase-1 (with associated processing and secretion of IL-1beta), and activation of NF-kappaB (a transcription factor involved in both initiation and resolution of the inflammatory response). Through PyD:PyD interactions, pyrin and cryopyrin, as well as several related, but still uncharacterized PyD containing proteins, appear to modulate the activity of all three of these processes, each of which plays a crucial role in the inflammatory pathways that characterize the innate immune system.
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PMID:Fire and ICE: the role of pyrin domain-containing proteins in inflammation and apoptosis. 1237 36

PYRIN-containing Apaf-1-like proteins (PYPAFs) are a recently identified family of proteins thought to function in apoptotic and inflammatory signaling pathways. PYPAF1 and PYPAF7 proteins have been found to assemble with the PYRIN-CARD protein ASC and coordinate the activation of NF-kappaB and pro-caspase-1. To determine if other PYPAF family members function in pro-inflammatory signaling pathways, we screened five other PYPAF proteins (PYPAF2, PYPAF3, PYPAF4, PYPAF5 and PYPAF6) for their ability to activate NF-kappaB and pro-caspase-1. Co-expression of PYPAF5 with ASC results in a synergistic activation of NF-kappaB and the recruitment of PYPAF5 to punctate structures in the cytoplasm. The expression of PYPAF5 is highly restricted to granulocytes and T-cells, indicating a role for this protein in inflammatory signaling. In contrast, PYPAF2, PYPAF3, PYPAF4 and PYPAF6 failed to colocalize with ASC and activate NF-kappaB. PYPAF5 also synergistically activated caspase-1-dependent cytokine processing when co-expressed with ASC. These findings suggest that PYPAF5 functions in immune cells to coordinate the transduction of pro-inflammatory signals to the activation of NF-kappaB and pro-caspase-1.
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PMID:Functional screening of five PYPAF family members identifies PYPAF5 as a novel regulator of NF-kappaB and caspase-1. 1238 69

PYRIN- and CARD-containing proteins belong to a recently identified protein family involved in the regulation of apoptosis and inflammatory processes. Variations in the gene products of the family members PYPAF1 and NOD2/CARD15 have been associated with several autoinflammatory diseases. We could identify the mouse orthologs of PYPAF1, PYPAF5, NOD1, NOD2 and the rat ortholog of PYPAF5. Intriguingly, we found that PYPAF5 has been reported previously not only as regulator of NF-kappaB and caspase-1, but also as angiotensin II and vasopressin receptor. In particular, based on a comprehensive sequence analysis, we propose a structural model for this hormone receptor that is different from the model suggested previously.
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PMID:Identification of mammalian orthologs associates PYPAF5 with distinct functional roles. 1263 74

Proteins containing PAAD [pyrin, AIM (absent-in-melanoma), ASC [apoptosis-associated speck-like protein containing a CARD (caspase-recruitment domain)] and DD (death domain)-like] (PYRIN, DAPIN) domains are involved in innate immunity, regulating pathways leading to nuclear-factor-kappa B (NF-kappa B) and pro-caspase-1 activation. Many PAAD-family proteins have structures reminiscent of Nod-1, a putative intracellular sensor of lipopolysaccharide. Hereditary mutations in some of the PAAD-family genes are associated with auto-inflammatory diseases. Several of these proteins utilize the bipartite PAAD- and CARD-containing adapter protein ASC/TMS-1 (target of methylation-induced silencing) for linking to downstream signalling pathways. In the present paper, we describe characterization of human PAAD-only protein-1 (POP1)/ASC2, which is highly homologous with the PAAD domain of ASC, and which probably originated by gene duplication on chromosome 16. We demonstrate that POP1/ASC2 associates with ASC via PAAD-PAAD interactions and modulates NF-kappa B and pro-caspase-1 regulation by this adapter protein. In gene transfer experiments, POP1/ASC2 suppressed cytokine-mediated NF-kappa B activation similar to other PAAD-family proteins previously tested. Immunohistochemical studies showed expression of POP1/ASC2 predominantly in macrophages and granulocytes. We propose that POP1/ASC2 functions as a modulator of multidomain PAAD-containing proteins involved in NF-kappa B and pro-caspase-1 activation and innate immunity.
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PMID:The PAAD/PYRIN-only protein POP1/ASC2 is a modulator of ASC-mediated nuclear-factor-kappa B and pro-caspase-1 regulation. 1293 66

Familial Mediterranean fever (FMF) is an inherited disorder characterized by recurrent episodes of fever and inflammation. Most patients with FMF carry missense mutations in the C-terminal half of the pyrin protein. To study the physiologic role of pyrin, we generated mice expressing a truncated pyrin molecule that, similar to FMF patients, retains the full PYRIN domain. Bacterial lipopolysaccharide (LPS) induces accentuated body temperatures and increased lethality in homozygous mutant mice. When stimulated, macrophages from these mice produce increased amounts of activated caspase-1 and, consequently, elevated levels of mature IL-1beta. Full-length pyrin competes in vitro with caspase-1 for binding to ASC, a known caspase-1 activator. Apoptosis is impaired in macrophages from pyrin-truncation mice through an IL-1-independent pathway. These data support a critical role for pyrin in the innate immune response, possibly by acting on ASC, and suggest a biologic basis for the selection of hypomorphic pyrin variants in man.
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PMID:Targeted disruption of pyrin, the FMF protein, causes heightened sensitivity to endotoxin and a defect in macrophage apoptosis. 1266 44

Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC)/target of methylation-induced silencing/PYCARD represents one of only two proteins encoded in the human genome that contains a caspase recruitment domain (CARD) together with a pyrin, AIM, ASC, and death domain-like (PAAD)/PYRIN/DAPIN domain. CARDs regulate caspase family proteases. We show here that ASC binds by its CARD to procaspase-1 and to adapter proteins involved in caspase-1 activation, thereby regulating cytokine pro-IL-1beta activation by this protease in THP-1 monocytes. ASC enhances IL-1beta secretion into the cell culture supernatants, at low concentrations, while suppressing at high concentrations. When expressed in HEK293 cells, ASC interferes with Cardiak/Rip2/Rick-mediated oligomerization of procaspase-1 and suppresses activation this protease, as measured by protease activity assays. Moreover, ASC also recruits procaspase-1 into ASC-formed cytosolic specks, separating it from Cardiak. We also show that expression of the PAAD/PYRIN family proteins pyrin or cryopyrin/PYPAF1/NALP3 individually inhibits IL-1beta secretion but that coexpression of ASC with these proteins results in enhanced IL-1beta secretion. However, expression of ASC uniformly interferes with caspase-1 activation and IL-1beta secretion induced by proinflammatory stimuli such as LPS and TNF, suggesting pathway competition. Moreover, LPS and TNF induce increases in ASC mRNA and protein expression in cells of myeloid/monocytic origin, revealing another level of cross-talk of cytokine-signaling pathways with the ASC-controlled pathway. Thus, our results suggest a complex interplay of the bipartite adapter protein ASC with PAAD/PYRIN family proteins, LPS (Toll family receptors), and TNF in the regulation of procaspase-1 activation, cytokine production, and control of inflammatory responses.
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PMID:Apoptosis-associated speck-like protein containing a caspase recruitment domain is a regulator of procaspase-1 activation. 1463 31

Recently, a large subfamily of nucleotide-binding and oligomerization domain-containing proteins that have an N-terminal pyrin-like domain and C-terminal leucine-rich repeats has been described. In this study, we identified PYNOD, a novel member of this family that lacks the leucine-rich repeats. We found that human PYNOD mRNA is expressed in various tissues and at high levels in heart, skeletal muscle and brain. It is also expressed in various cell lines, including haematopoietic cell lines. PYNOD oligomerizes and binds to ASC, an adaptor protein that plays a role in apoptotic and inflammatory signal transduction, and to caspase-1 and IL-1beta. PYNOD inhibits apoptosis-associated speck-like protein containing a CARD (ASC)-mediated NF-kappaB activation and apoptosis, and caspase-1-mediated IL-1beta maturation, and it does so in the presence and absence of constitutively active mutants of CARD12 and PYPAF1, which are enhancers of these processes. Thus, PYNOD is a novel regulator of apoptosis and inflammation.
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PMID:PYNOD, a novel Apaf-1/CED4-like protein is an inhibitor of ASC and caspase-1. 1509 76


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