Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.15.1 (ACE)
 18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Site-specific proteases play critical roles in regulating many cellular processes. To identify novel site-specific proteases, their regulators, and substrates, we have designed a general reporter system in Saccharomyces cerevisiae in which a transcription factor is linked to the intracellular domain of a transmembrane protein by protease cleavage sites. Here, we explore the efficacy of this approach by using caspases, a family of aspartate-specific cysteine proteases, as a model. Introduction of an active caspase into cells that express a caspase-cleavable reporter results in the release of the transcription factor from the membrane and subsequent activation of a nuclear reporter. We show that known caspases activate the reporter, that an activator of caspase activity stimulates reporter activation in the presence of an otherwise inactive caspase, and that caspase inhibitors suppress caspase-dependent reporter activity. We also find that, although low or moderate levels of active caspase expression do not compromise yeast cell growth, higher level expression leads to lethality. We have exploited this observation to isolate clones from a Drosophila embryo cDNA library that block DCP-1 caspase-dependent yeast cell death. Among these clones, we identified the known cell death inhibitor DIAP1. We showed, by using bacterially synthesized proteins, that glutathione S-transferase-DIAP1 directly inhibits DCP-1 caspase activity but that it had minimal effect on the activity of a predomainless version of a second Drosophila caspase, drICE.
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PMID:A cloning method to identify caspases and their regulators in yeast: identification of Drosophila IAP1 as an inhibitor of the Drosophila caspase DCP-1. 1007 6

In Drosophila, the APAF-1 homolog ARK is required for the activation of the initiator caspase DRONC, which in turn cleaves the effector caspases DRICE and DCP-1. While the function of ARK is important in stress-induced apoptosis in Drosophila S2 cells, as its removal completely suppresses cell death, the decision to undergo apoptosis appears to be regulated at the level of caspase activation, which is controlled by the IAP proteins, particularly DIAP1. Here, we further dissect the apoptotic pathways induced in Drosophila S2 cells in response to stressors and in response to knock-down of DIAP1. We found that the induction of apoptosis was dependent in each case on expression of ARK and DRONC and surviving cells continued to proliferate. We noted a difference in the effects of silencing the executioner caspases DCP-1 and DRICE; knock-down of either or both of these had dramatic effects to sustain cell survival following depletion of DIAP1, but had only minor effects following cellular stress. Our results suggest that the executioner caspases are essential for death following DIAP1 knock-down, indicating that the initiator caspase DRONC may lack executioner functions. The apparent absence of mitochondrial outer membrane permeabilization (MOMP) in Drosophila apoptosis may permit the cell to thrive when caspase activation is disrupted.
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PMID:Cell survival and proliferation in Drosophila S2 cells following apoptotic stress in the absence of the APAF-1 homolog, ARK, or downstream caspases. 1653 75

In this issue of Molecular Cell, Ditzel et al. (2008) show that DIAP1 polyubiquitinates DRONC, DCP-1, and drICE, leading to their nondegradative inactivation. Surprisingly, activation of DIAP1 requires caspase-mediated cleavage, revealing an elegant feedback mechanism by which caspases regulate their own fate.
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PMID:Caspases and IAPs: a dance of death ensures cell survival. 1902 84