Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.61 (caspase-8)
 6,833 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fas/APO-1 and p55 tumor necrosis factor (TNF) receptor (p55-R) activate cellular mechanisms that result in cell death. Upon activation of these receptors, Fas/APO-1 binds a protein called MORT1 (or FADD) and p55-R binds a protein called TRADD. MORT1 and TRADD can also bind to each other. We have cloned a novel protein, MACH, that binds to MORT1. This protein exists in multiple isoforms, some of which contain a region that has proteolytic activity and shows marked sequence homology to proteases of the ICE/CED-3 family. Cellular expression of the proteolytic MACH isoforms results in cell death. Expression of MACH isoforms that contain an incomplete ICE/CED-3 region provides effective protection against the cytotoxicity induced by Fas/APO-1 or p55-R triggering. These findings suggest that MACH is the most upstream enzymatic component in the Fas/APO-1- and p55-R-induced cell death signaling cascades.
 ...
PMID:Involvement of MACH, a novel MORT1/FADD-interacting protease, in Fas/APO-1- and TNF receptor-induced cell death. 868 76

To identify CAP3 and CAP4, components of the CD95 (Fas/APO-1) death-inducing signaling complex, we utilized nano-electrospray tandem mass spectrometry, a recently developed technique to sequence femtomole quantities of polyacrylamide gel-separated proteins. Interestingly, CAP4 encodes a novel 55 kDa protein, designated FLICE, which has homology to both FADD and the ICE/CED-3 family of cysteine proteases. FLICE binds to the death effector domain of FADD and upon overexpression induces apoptosis that is blocked by the ICE family inhibitors, CrmA and z-VAD-fmk. CAP3 was identified as the FLICE prodomain which likely remains bound to the receptor after proteolytic activation. Taken together, this is unique biochemical evidence to link a death receptor physically to the proapoptotic proteases of the ICE/CED-3 family.
 ...
PMID:FLICE, a novel FADD-homologous ICE/CED-3-like protease, is recruited to the CD95 (Fas/APO-1) death--inducing signaling complex. 868 77

Engagement of CD95 or tumor necrosis factor 1 receptor (TNFR-1) by ligand or agonist antibodies is capable of activating the cell death program, the effector arm of which is composed of mammalian interleukin-1beta converting enzyme (ICE)-like cysteine proteases (designated caspases) that are related to the Caenorhabditis elegans death gene, CED-3. Caspases, unlike other mammalian cysteine proteases, cleave their substrates following aspartate residues. Furthermore, proteases belonging to this family exist as zymogens that in turn require cleavage at internal aspartate residues to generate the two-subunit active enzyme. As such, family members are capable of activating each other. Remarkably, both CD95 and TNFR-1 death receptors initiate apoptosis by recruiting a novel ICE/CED-3 family member, designated FLICE/MACH, to the receptor signaling complex. Therefore, FLICE/MACH represents the apical triggering protease in the cascade. Consistent with this, recombinant FLICE was found capable of proteolytically activating downstream caspases. Furthermore, CrmA, a pox virus-encoded serpin that inhibits Fas and tumor necrosis factor-induced cell death attenuates the ability of FLICE to activate downstream caspases.
 ...
PMID:FLICE induced apoptosis in a cell-free system. Cleavage of caspase zymogens. 900 41

Apoptosis is a major form of cell death, characterized initially by a series of stereotypic morphological changes. In the nematode Caenorhabditis elegans, the gene ced-3 encodes a protein required for developmental cell death. Since the recognition that CED-3 has sequence identity with the mammalian cysteine protease interleukin-1 beta-converting enzyme (ICE), a family of at least 10 related cysteine proteases has been identified. These proteins are characterized by almost absolute specificity for aspartic acid in the P1 position. All the caspases (ICE-like proteases) contain a conserved QACXG (where X is R, Q or G) pentapeptide active-site motif. Capases are synthesized as inactive proenzymes comprising an N-terminal peptide (prodomain) together with one large and one small subunit. The crystal structures of both caspase-1 and caspase-3 show that the active enzyme is a heterotetramer, containing two small and two large subunits. Activation of caspases during apoptosis results in the cleavage of critical cellular substrates, including poly(ADP-ribose) polymerase and lamins, so precipitating the dramatic morphological changes of apoptosis. Apoptosis induced by CD95 (Fas/APO-1) and tumour necrosis factor activates caspase-8 (MACH/FLICE/Mch5), which contains an N-terminus with FADD (Fas-associating protein with death domain)-like death effector domains, so providing a direct link between cell death receptors and the caspases. The importance of caspase prodomains in the regulation of apoptosis is further highlighted by the recognition of adapter molecules, such as RAIDD [receptor-interacting protein (RIP)-associated ICH-1/CED-3-homologous protein with a death domain]/CRADD (caspase and RIP adapter with death domain), which binds to the prodomain of caspase-2 and recruits it to the signalling complex. Cells undergoing apoptosis following triggering of death receptors execute the death programme by activating a hierarchy of caspases, with caspase-8 and possibly caspase-10 being at or near the apex of this apoptotic cascade.
 ...
PMID:Caspases: the executioners of apoptosis. 933 44

Upon activation, cell surface death receptors, Fas/APO-1/CD95 and tumor necrosis factor receptor-1 (TNFR-1), are attached to cytosolic adaptor proteins, which in turn recruit caspase-8 (MACH/FLICE/Mch5) to activate the interleukin-1 beta-converting enzyme (ICE)/CED-3 family protease (caspase) cascade. However, it remains unknown whether these apoptotic proteases are generally involved in apoptosis triggered by other stimuli such as Myc and p53. In this study, we provide lines of evidence that a death protease cascade consisting of caspases and serine proteases plays an essential role in Myc-mediated apoptosis. When Rat-1 fibroblasts stably expressing either s-Myc or c-Myc were induced to undergo apoptosis by serum deprivation, a caspase-3 (CPP32)-like protease activity that cleaves a specific peptide substrate, Ac-DEVD-MCA, appeared in the cell lysates. Induction of s-Myc- and c-Myc-mediated apoptotic cell death was effectively prevented by caspase inhibitors such as Z-Asp-CH2-DCB and Ac-DEVD-CHO. Furthermore, exposing the cells to a serine protease inhibitor, 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF), also significantly inhibited s-Myc- and c-Myc-mediated apoptosis and the appearance of the caspase-3-like protease activity in vivo. However, AEBSF did not directly inhibit caspase-3-like protease activity in the apoptotic cell lysates in vitro. Together, these results indicate that caspase-3-like proteases play a critical role in both s-Myc- and c-Myc-mediated apoptosis and that caspase-3-like proteases function downstream of the AEBSF-sensitive step in the signaling pathway of Myc-mediated apoptosis.
 ...
PMID:A functional role for death proteases in s-Myc- and c-Myc-mediated apoptosis. 934 38

Recent studies indicate that Caenorhabditis elegans CED-4 interacts with and promotes the activation of the death protease CED-3, and that this activation is inhibited by CED-9. Here we show that a mammalian homolog of CED-4, Apaf-1, can associate with several death proteases, including caspase-4, caspase-8, caspase-9, and nematode CED-3 in mammalian cells. The interaction with caspase-9 was mediated by the N-terminal CED-4-like domain of Apaf-1. Expression of Apaf-1 enhanced the killing activity of caspase-9 that required the CED-4-like domain of Apaf-1. Furthermore, Apaf-1 promoted the processing and activation of caspase-9 in vivo. Bcl-XL, an antiapoptotic member of the Bcl-2 family, was shown to physically interact with Apaf-1 and caspase-9 in mammalian cells. The association of Apaf-1 with Bcl-XL was mediated through both its CED-4-like domain and the C-terminal domain containing WD-40 repeats. Expression of Bcl-XL inhibited the association of Apaf-1 with caspase-9 in mammalian cells. Significantly, recombinant Bcl-XL purified from Escherichia coli or insect cells inhibited Apaf-1-dependent processing of caspase-9. Furthermore, Bcl-XL failed to inhibit caspase-9 processing mediated by a constitutively active Apaf-1 mutant, suggesting that Bcl-XL regulates caspase-9 through Apaf-1. These experiments demonstrate that Bcl-XL associates with caspase-9 and Apaf-1, and show that Bcl-XL inhibits the maturation of caspase-9 mediated by Apaf-1, a process that is evolutionarily conserved from nematodes to humans.
 ...
PMID:Bcl-XL interacts with Apaf-1 and inhibits Apaf-1-dependent caspase-9 activation. 953 46

We have identified and characterized ARC, apoptosis repressor with caspase recruitment domain (CARD). Sequence analysis revealed that ARC contains an N-terminal CARD fused to a C-terminal region rich in proline/glutamic acid residues. The CARD domain of ARC exhibited significant homology to the prodomains of apical caspases and the CARDs present in the cell death regulators Apaf-1 and RAIDD. Immunoprecipitation analysis revealed that ARC interacts with caspase-2, -8, and Caenorhabditis elegans CED-3, but not with caspase-1, -3, or -9. ARC inhibited apoptosis induced by caspase-8 and CED-3 but not that mediated by caspase-9. Further analysis showed that the enzymatic activity of caspase-8 was inhibited by ARC in 293T cells. Consistent with the inhibition of caspase-8, ARC attenuated apoptosis induced by FADD and TRADD and that triggered by stimulation of death receptors coupled to caspase-8, including CD95/Fas, tumor necrosis factor-R1, and TRAMP/DR3. Remarkably, the expression of human ARC was primarily restricted to skeletal muscle and cardiac tissue. Thus, ARC represents an inhibitor of apoptosis expressed in muscle that appears to selectively target caspases. Delivery of ARC by gene transfer or enhancement of its endogenous activity may provide a strategy for the treatment of diseases that are characterized by inappropriately increased cell death in muscle tissue.
 ...
PMID:ARC, an inhibitor of apoptosis expressed in skeletal muscle and heart that interacts selectively with caspases. 956 Feb 45

Programmed cell death, or apoptosis, is a process of fundamental importance to cellular homeostasis in metazoan organisms (Ellis, R. E., Yuan, J., and Horvitz, H. R. (1991) Annu. Rev. Cell Biol. 7, 663-698). The caspase family of mammalian proteases, related to the nematode death protein CED-3, plays a crucial role in apoptosis and inflammation. We report here the isolation and characterization of a new caspase, tentatively termed ERICE (Evolutionarily Related Interleukin-1beta Converting Enzyme). Based on phylogenetic analysis, ERICE (caspase-13) is a member of the ICE subfamily of caspases which includes caspase-1 (ICE), caspase-4 (ICErel-II, TX, ICH-2), and caspase-5 (ICErel-III, TY). Overexpression of ERICE induces apoptosis of 293 human embryonic kidney cells and MCF7 breast carcinoma cells. Like other members of the subfamily, ERICE is not activated by the serine protease granzyme B, a caspase-activating component of cytotoxic T cell granules. Therefore, ERICE most likely does not play a role in granzyme B-induced cell death. ERICE, however, was activated by caspase-8 (FLICE, MACH, Mch-5), the apical caspase activated upon engagement of death receptors belonging to the tumor necrosis factor family. This is consistent with a potential role for ERICE in this receptor-initiated death pathway.
 ...
PMID:ERICE, a novel FLICE-activatable caspase. 962 66

Recent studies have implicated Fas in the pathogenesis of inflammatory, ischemic, and traumatic brain injury (TBI); however, a direct link between Fas activation and caspase-mediated cell death has not been established in injured brain. We detected Fas-Fas ligand binding and assembly of death-inducing signaling complexes (DISCs) [Fas, Fas-associated protein with death domain, and procaspase-8 or procaspase-10; receptor interacting protein (RIP)-RIP-associated interleukin-1beta converting enzyme and CED-3 homolog-1/Ced 3 homologous protein with a death domain-procaspase-2] by immunoprecipitation and immunoblotting within mouse parietal cortex after controlled cortical impact. At the time of DISC assembly, procaspase-8 was cleaved and the cleavage product appeared at 48 hr in terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling-positive neurons. Cleavage of caspase-8 was accompanied by caspase-3 processing detected at 48 hr by immunohistochemistry, and by caspase-specific cleavage of poly(ADP-ribose) polymerase at 12 hr. Fas pathways were also stimulated by TBI in human brain, because Fas expression plus Fas-procaspase-8 interaction were robust in contused cortical tissue samples surgically removed between 2 and 30 hr after injury. To address whether Fas functions as a death receptor in brain cells, cultured embryonic day 17 cortical neurons were transfected with an adenoviral vector containing the gene encoding Fas ligand. After 48 hr in culture, Fas ligand expression and Fas-procaspase-8 DISC assembly increased, and by 72 hr, cell death was pronounced. Cell death was decreased by approximately 50% after pan-caspase inhibition (Z-Val-ALa-Asp(Ome)-fluoromethylketone). These data suggest that Fas-associated DISCs assemble in neurons overexpressing Fas ligand as well as within mouse and human contused brain after TBI. Therefore, Fas may function as a death receptor after brain injury.
 ...
PMID:Upregulation of the Fas receptor death-inducing signaling complex after traumatic brain injury in mice and humans. 1197 27

Apoptosome refers to the adaptor protein complex that mediates the activation of an initiator caspase at the onset of apoptosis. In mammalian cells, caspase-9, caspase-8, and caspase-2 rely on the apoptotic protease-activating factor 1 (Apaf-1)-apoptosome, death-inducing signaling complex (DISC), and PIDDosome, respectively, for activation. In Drosophila, activation of the caspase-9 homolog Dronc requires assembly of an apoptosome comprised of Dark/Hac-1/Dapaf-1. In Caenorhabditis elegans, activation of the caspase CED-3 is facilitated by the CED-4-apoptosome. Recent biochemical and structural investigation revealed significant insights into the assembly and function of the various apoptosomes. Nonetheless, conclusive mechanisms by which the initiator caspases are activated by the apoptosomes remain elusive. Several models have been proposed to explain the activation process. The induced proximity model summarizes the general process of initiator caspase activation. The proximity-driven dimerization model describes how initiator caspases respond to induced proximity and offers an explanation for their activation. Regardless of how initiator caspases are activated, enhanced activity must be correlated with altered active site conformation. The induced conformation model posits that the activated conformation for the active site of a given initiator caspase is attained through direct interaction with the apoptosome or through homo-oligomerization facilitated by the apoptosome.
 ...
PMID:Apoptosome: a platform for the activation of initiator caspases. 1697 32


1 2 Next >>