scholarly journals Genetic and metabolic status of NGF-deprived sympathetic neurons saved by an inhibitor of ICE family proteases.

1996 ◽  
Vol 135 (5) ◽  
pp. 1341-1354 ◽  
Author(s):  
M Deshmukh ◽  
J Vasilakos ◽  
T L Deckwerth ◽  
P A Lampe ◽  
B D Shivers ◽  
...  

Sympathetic neurons undergo programmed cell death (PCD) when deprived of NGF. We used an inhibitor to examine the function of interleukin-1 beta-converting enzyme (ICE) family proteases during sympathetic neuronal death and to assess the metabolic and genetic status of neurons saved by such inhibition. Bocaspartyl(OMe)-fluoromethylketone (BAF), a cell-permeable inhibitor of the ICE family of cysteine proteases, inhibited ICE and CPP32 (IC50 approximately 4 microM) in vitro and blocked Fas-mediated apoptosis in thymocytes (EC50 approximately 10 microM). At similar concentrations, BAF also blocked the NGF deprivation-induced death of rat sympathetic neurons in culture. Compared to NGF-maintained neurons, BAF-saved neurons had markedly smaller somas and maintained only basal levels of protein synthesis; readdition of NGF restored growth and metabolism. Although BAF blocked apoptosis in sympathetic neurons, it did not prevent the fall in protein synthesis or the increase in the expression of c-jun, c-fos, and other mRNAs that occur during neuronal PCD, implying that the ICE-family proteases function downstream of these events during PCD.NGF and BAF rescued sympathetic neurons with an identical time course, suggesting that NGF, in addition to inhibiting metabolic and genetic events associated with neuronal PCD, can act posttranslationally to abort apoptosis at a time point indistinguishable from the activation of cysteine proteases. Both poly-(ADP ribose) polymerase and pro-ICE and Ced-3 homolog-1 (ICH-1) appear to be cleaved in a BAF-inhibitable manner, although the majority of pro-CPP32 appears unchanged, suggesting that ICH-1 is activated during neuronal PCD. Potential implications of these findings for anti-apoptotic therapies are discussed.

2007 ◽  
Vol 403 (3) ◽  
pp. 451-461 ◽  
Author(s):  
Sandrine Pacquelet ◽  
Jennifer L. Johnson ◽  
Beverly A. Ellis ◽  
Agnieszka A. Brzezinska ◽  
William S. Lane ◽  
...  

Exposure of neutrophils to LPS (lipopolysaccharide) triggers their oxidative response. However, the relationship between the signalling downstream of TLR4 (Toll-like receptor 4) after LPS stimulation and the activation of the oxidase remains elusive. Phosphorylation of the cytosolic factor p47phox is essential for activation of the NADPH oxidase. In the present study, we examined the hypothesis that IRAK-4 (interleukin-1 receptor-associated kinase-4), the main regulatory kinase downstream of TLR4 activation, regulates the NADPH oxidase through phosphorylation of p47phox. We show that p47phox is a substrate for IRAK-4. Unlike PKC (protein kinase C), IRAK-4 phosphorylates p47phox not only at serine residues, but also at threonine residues. Target residues were identified by tandem MS, revealing a novel threonine-rich regulatory domain. We also show that p47phox is phosphorylated in granulocytes in response to LPS stimulation. LPS-dependent phosphorylation of p47phox was enhanced by the inhibition of p38 MAPK (mitogen-activated protein kinase), confirming that the kinase operates upstream of p38 MAPK. IRAK-4-phosphorylated p47phox activated the NADPH oxidase in a cell-free system, and IRAK-4 overexpression increased NADPH oxidase activity in response to LPS. We have shown that endogenous IRAK-4 interacts with p47phox and they co-localize at the plasma membrane after LPS stimulation, using immunoprecipitation assays and immunofluorescence microscopy respectively. IRAK-4 was activated in neutrophils in response to LPS stimulation. We found that Thr133, Ser288 and Thr356, targets for IRAK-4 phosphorylation in vitro, are also phosphorylated in endogenous p47phox after LPS stimulation. We conclude that IRAK-4 phosphorylates p47phox and regulates NADPH oxidase activation after LPS stimulation.


Weed Science ◽  
1980 ◽  
Vol 28 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Luanne M. Deal ◽  
J. T. Reeves ◽  
B. A. Larkins ◽  
F. D. Hess

The effects of chloracetamides on protein synthesis were studied both in vivo and in vitro. Four chloracetamide herbicides, alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], CDAA (N–N-diallyl-2-chloroacetamide), and propachlor (2-chloro-N-isopropylacetanilide) were tested for inhibition of [3H]-leucine incorporation into protein. Incorporation of3H-leucine into trichloroacetic acid (TCA)-insoluble protein was inhibited in oat (Avena sativaL. ‘Victory’) seedlings grown in sand culture and treated 12 h at 1 × 10−4M with these chloracetamides. The herbicides were also tested in a cell-free protein synthesizing system containing polyribosomes purified from oat root cytoplasm. These herbicides had no effect on the rates of polypeptide elongation nor on the synthesis of specific polypeptides when herbicides (1 × 10−4M) were added directly to the system. Polypeptide formation was inhibited 89% when 1 × 10−4M cycloheximide was added during translation. Cytoplasmic polyribosomes were isolated from oat roots treated 12 h with 1 × 10−4M herbicide. Translation rates and products were not altered when these polyribosomes were added to the in vitro system. Protein synthesis is inhibited when tested in an in vivo system; however, the inhibition does not occur during the translation of mRNA into protein.


Author(s):  
Dan Smelter ◽  
Mary Hayney ◽  
George Sakoulas ◽  
Warren Rose

Cefazolin and ertapenem has been shown to be an effective salvage regimen for refractory methicillin-susceptible Staphylococcus aureus bacteremia. Our findings suggest cefazolin plus ertapenem in vitro stimulates interleukin-1β release from peripheral blood monocytes both with and without S. aureus presence. This IL-1β augmentation was primarily driven by ertapenem. These findings support further exploration of cefazolin plus ertapenem in MSSA bacteremia and may partially explain its marked potency in vivo despite modest synergy in vitro .


1996 ◽  
Vol 133 (5) ◽  
pp. 1041-1051 ◽  
Author(s):  
M D Jacobsen ◽  
M Weil ◽  
M C Raff

In the accompanying paper by Weil et al. (1996) we show that staurosporine (STS), in the presence of cycloheximide (CHX) to inhibit protein synthesis, induces apoptotic cell death in a large variety of nucleated mammalian cell types, suggesting that all nucleated mammalian cells constitutively express all of the proteins required to undergo programmed cell death (PCD). The reliability of that conclusion depends on the evidence that STS-induced, and (STS + CHS)-induced, cell deaths are bona fide examples of PCD. There is rapidly accumulating evidence that some members of the Ced-3/Interleukin-1 beta converting enzyme (ICE) family of cysteine proteases are part of the basic machinery of PCD. Here we show that Z-Val-Ala-Asp-fluoromethylketone (zVAD-fmk), a cell-permeable, irreversible, tripeptide inhibitor of some of these proteases, suppresses STS-induced and (STS + CHX)-induced cell death in a wide variety of mammalian cell types, including anucleate cytoplasts, providing strong evidence that these are all bona fide examples of PCD. We show that the Ced-3/ICE family member CPP32 becomes activated in STS-induced PCD, and that Bcl-2 inhibits this activation. Most important, we show that, in some cells at least, one or more CPP32-family members, but not ICE itself, is required for STS-induced PCD. Finally, we show that zVAD-fmk suppresses PCD in the interdigital webs in developing mouse paws and blocks the removal of web tissue during digit development, suggesting that this inhibition will be a useful tool for investigating the roles of PCD in various developmental processes.


2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Takehiro Nishikawa ◽  
Takeshi Sunami ◽  
Tomoaki Matsuura ◽  
Tetsuya Yomo

Directed evolution of proteins is a technique used to modify protein functions through “Darwinian selection.”In vitrocompartmentalization (IVC) is anin vitrogene screening system for directed evolution of proteins. IVC establishes the link between genetic information (genotype) and the protein translated from the information (phenotype), which is essential for all directed evolution methods, by encapsulating both in a nonliving microcompartment. Herein, we introduce a new liposome-based IVC system consisting of a liposome, the protein synthesis using recombinant elements (PURE) system and a fluorescence-activated cell sorter (FACS) used as a microcompartment,in vitroprotein synthesis system, and high-throughput screen, respectively. Liposome-based IVC is characterized byin vitroprotein synthesis from a single copy of a gene in a cell-sized unilamellar liposome and quantitative functional evaluation of the synthesized proteins. Examples of liposome-based IVC for screening proteins such as GFP andβ-glucuronidase are described. We discuss the future directions for this method and its applications.


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