scholarly journals Characterization of reaper- and FADD-induced apoptosis in a lepidopteran cell line.

1997 ◽  
Vol 17 (2) ◽  
pp. 667-676 ◽  
Author(s):  
D Vucic ◽  
S Seshagiri ◽  
L K Miller

Expression of the reaper gene (rpr) correlates with the initiation of apoptosis in Drosophila melanogaster. Transient expression of rpr in the lepidopteran SF-21 cell line induced apoptosis displaying nuclear condensation and fragmentation, oligonucleosomal ladder formation, cell surface blebbing, and apoptotic body formation. Inhibitors of ICE-family proteases p35 and crmA, as well as members of the iap class of genes, Op-iap and D-iap2, but not bcl-2 family members, blocked rpr-induced apoptosis. Mutational analysis of rpr provided no support for the proposed sequence similarity of Reaper and death domain proteins. Mutations in the N-terminal region of Reaper, which displays sequence similarity to Hid and Grim, other Drosophila gene products correlated with the initiation of apoptosis, suggested that these residues might be functionally important. The mammalian cDNA encoding FADD (Fas-associating protein with a death domain) also induced cell death in SF-21 cells, but death progressed more slowly and with features which distinguished it from rpr-induced apoptosis. Several bcl-2 family members delayed or blocked FADD-induced cellular death. Thus, apoptosis initiated by Reaper progressed by a faster path which appeared to differ from that of FADD-induced apoptosis.

1999 ◽  
Vol 19 (10) ◽  
pp. 6500-6508 ◽  
Author(s):  
Nanette J. Pazdernik ◽  
David B. Donner ◽  
Mark G. Goebl ◽  
Maureen A. Harrington

ABSTRACT The death domain-containing receptor superfamily and their respective downstream mediators control whether or not cells initiate apoptosis or activate NF-κB, events critical for proper immune system function. A screen for upstream activators of NF-κB identified a novel serine-threonine kinase capable of activating NF-κB and inducing apoptosis. Based upon domain organization and sequence similarity, this novel kinase, named mRIP3 (mouse receptor interacting protein 3), appears to be a new RIP family member. RIP, RIP2, and mRIP3 contain an N-terminal kinase domain that share 30 to 40% homology. In contrast to the C-terminal death domain found in RIP or the C-terminal caspase-recruiting domain found in RIP2, the C-terminal tail of mRIP3 contains neither motif and is unique. Despite this feature, overexpression of the mRIP3 C terminus is sufficient to induce apoptosis, suggesting that mRIP3 uses a novel mechanism to induce death. mRIP3 also induced NF-κB activity which was inhibited by overexpression of either dominant-negative NIK or dominant-negative TRAF2. In vitro kinase assays demonstrate that mRIP3 is catalytically active and has autophosphorylation site(s) in the C-terminal domain, but the mRIP3 catalytic activity is not required for mRIP3 induced apoptosis and NF-κB activation. Unlike RIP and RIP2, mRIP3 mRNA is expressed in a subset of adult tissues and is thus likely to be a tissue-specific regulator of apoptosis and NF-κB activity. While the lack of a dominant-negative mutant precludes linking mRIP3 to a known upstream regulator, characterizing the expression pattern and the in vitro functions of mRIP3 provides insight into the mechanism(s) by which cells modulate the balance between survival and death in a cell-type-specific manner.


1994 ◽  
Vol 14 (6) ◽  
pp. 3895-3905
Author(s):  
S Kjaerulff ◽  
J Davey ◽  
O Nielsen

We previously identified two genes, mfm1 and mfm2, with the potential to encode the M-factor mating pheromone of the fission yeast Schizosaccharomyces pombe (J. Davey, EMBO J. 11:951-960, 1992), but further analysis revealed that a mutant strain lacking both genes still produced active M-factor. Here we describe the isolation and characterization of a third M-factor gene, mfm3. A mutant lacking all three genes fails to produce M-factor, indicating that all functional M-factor genes now have been identified. The triple mutant exhibits an absolute mating defect in M cells, a defect that is not rescued by addition of exogenous M-factor. A mutational analysis reveals that all three mfm genes contribute to the production of M-factor. Their transcription is limited to M cells and requires the mat1-Mc and ste11 gene products. Each gene is induced when the cells are starved of nitrogen and further induced by a pheromone signal. Additionally, the signal transduction machinery associated with the pheromone response is required for transcription of the mfm genes in both stimulated and unstimulated cells.


1998 ◽  
Vol 18 (6) ◽  
pp. 3300-3309 ◽  
Author(s):  
Domagoj Vucic ◽  
William J. Kaiser ◽  
Lois K. Miller

ABSTRACT Reaper (RPR), HID, and GRIM activate apoptosis in cells programmed to die during Drosophila development. We have previously shown that transient overexpression of RPR in the lepidopteran SF-21 cell line induces apoptosis and that members of the inhibitor of apoptosis (IAP) family of antiapoptotic proteins can inhibit RPR-induced apoptosis and physically interact with RPR through their BIR motifs (D. Vucic, W. J. Kaiser, A. J. Harvey, and L. K. Miller, Proc. Natl. Acad. Sci. USA 94:10183–10188, 1997). In this study, we found that transient overexpression of HID and GRIM also induced apoptosis in the SF-21 cell line. Baculovirus and Drosophila IAPs blocked HID- and GRIM-induced apoptosis and also physically interacted with them through the BIR motifs of the IAPs. The region of sequence similarity shared by RPR, HID, and GRIM, the N-terminal 14 amino acids of each protein, was required for the induction of apoptosis by HID and its binding to IAPs. When stably overexpressed by fusion to an unrelated, nonapoptotic polypeptide, the N-terminal 37 amino acids of HID and GRIM were sufficient to induce apoptosis and confer IAP binding activity. However, GRIM was more complex than HID since the C-terminal 124 amino acids of GRIM retained apoptosis-inducing and IAP binding activity, suggesting the presence of two independent apoptotic motifs within GRIM. Coexpression of IAPs with HID stabilized HID levels and resulted in the accumulation of HID in punctate perinuclear locations which coincided with IAP localization. The physical interaction of IAPs with RPR, HID, and GRIM provides a common molecular mechanism for IAP inhibition of theseDrosophila proapoptotic proteins.


2001 ◽  
Vol 280 (6) ◽  
pp. F1107-F1114 ◽  
Author(s):  
Elif Erkan ◽  
Maryely De Leon ◽  
Prasad Devarajan

The degree of albuminuria is a well-known adverse prognostic indicator in human glomerular diseases. However, the mechanisms by which albuminuria by itself contributes to tubulointerstitial injury and progression of renal disease remain unclear. We tested the hypothesis that apoptosis may represent one of the mechanisms by which tubule epithelial cells are damaged after albumin overload in vitro. Cultured LLC-PK1 proximal tubule cells were incubated with varying concentrations of BSA. This resulted in a dose- and duration-dependent induction of apoptosis, as evidenced by internucleosomal DNA cleavage (DNA laddering and nick-end labeling), externalization of plasma membrane phosphatidylserine (annexin labeling), and characteristic morphological changes (cell shrinkage and nuclear condensation). Albumin overload also resulted in a dose-dependent upregulation of Fas and Fas-associated protein with death domain (FADD), and activation of caspase 8. Incubation with the caspase 8 inhibitor IETD ameliorated the albumin-induced apoptosis. Collectively, our results indicate that albumin overload induces apoptosis of cultured LLC-PK1 cells, mediated at least in part by the Fas-FADD-caspase 8 pathway.


1994 ◽  
Vol 14 (6) ◽  
pp. 3895-3905 ◽  
Author(s):  
S Kjaerulff ◽  
J Davey ◽  
O Nielsen

We previously identified two genes, mfm1 and mfm2, with the potential to encode the M-factor mating pheromone of the fission yeast Schizosaccharomyces pombe (J. Davey, EMBO J. 11:951-960, 1992), but further analysis revealed that a mutant strain lacking both genes still produced active M-factor. Here we describe the isolation and characterization of a third M-factor gene, mfm3. A mutant lacking all three genes fails to produce M-factor, indicating that all functional M-factor genes now have been identified. The triple mutant exhibits an absolute mating defect in M cells, a defect that is not rescued by addition of exogenous M-factor. A mutational analysis reveals that all three mfm genes contribute to the production of M-factor. Their transcription is limited to M cells and requires the mat1-Mc and ste11 gene products. Each gene is induced when the cells are starved of nitrogen and further induced by a pheromone signal. Additionally, the signal transduction machinery associated with the pheromone response is required for transcription of the mfm genes in both stimulated and unstimulated cells.


2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Samantha Przybelski ◽  
Massiel E. Ulloa ◽  
Melisa Rudie ◽  
Megan Cornett ◽  
David Strom

1999 ◽  
Vol 10 (10) ◽  
pp. 3251-3261 ◽  
Author(s):  
Jaleh Doostzadeh-Cizeron ◽  
Randall Evans ◽  
Shenmin Yin ◽  
David W. Goodrich

Rb protein inhibits both cell cycle progression and apoptosis. Interaction of specific cellular proteins, including E2F1, with Rb C-terminal domains mediates cell cycle regulation. In contrast, the nuclear N5 protein associates with an Rb N-terminal domain with unknown function. The N5 protein contains a region of sequence similarity to the death domain of proteins involved in apoptotic signaling. We demonstrate here that forced N5 expression potently induces apoptosis in several tumor cell lines. Mutation of conserved residues within the death domain homology compromise N5-induced apoptosis, suggesting that it is required for normal function. Endogenous N5 protein is specifically altered in apoptotic cells treated with ionizing radiation. Furthermore, dominant interfering death domain mutants compromise cellular responses to ionizing radiation. Finally, physical association with Rb protein inhibits N5-induced apoptosis. We propose that N5 protein plays a role in the regulation of apoptosis and that Rb directly coordinates cell proliferation and apoptosis by binding specific proteins involved in each process through distinct protein binding domains.


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