The short prodomain influences caspase-3 activation in HeLa cells

2000 ◽  
Vol 349 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Thomas MEERGANS ◽  
Ann-Kristin HILDEBRANDT ◽  
Daniel HORAK ◽  
Christina HAENISCH ◽  
Albrecht WENDEL
Keyword(s):  
Hela Cells ◽  
Mammalian Cells ◽  
Caspase 3 ◽  
Yeast Cells ◽  
Inhibitor Of Apoptosis ◽  
Proteolytic Activation ◽  
Inhibitor Of Apoptosis Protein ◽  
Apoptotic Protein ◽  
Autocatalytic Processing ◽  
Apoptosis Protein

Proteolytic activation of caspases is a key step in the process of apoptosis. According to their primary structure, caspases can be divided into a group with a long prodomain and a group with a short prodomain. Whereas long prodomains play a role in autocatalytic processing, little is known about the function of the short prodomain, for example the prodomain of caspase-3. We constructed caspase-3 variants lacking the prodomain and overexpressed these in HeLa and yeast cells. We found that removal of the caspase-3 prodomain resulted in spontaneous proteolytic activation of the protein when expressed in HeLa cells. This processing was only partially autocatalytic, as demonstrated by a catalytically inactive caspase-3 mutant. Co-expression of the anti-apoptotic protein XIAP (X-chromosome-linked inhibitor of apoptosis protein) completely blocked the observed spontaneous activation, which excluded a direct involvement of caspase-8. Our findings indicate that the short prodomain of caspase-3 serves as a silencing component in mammalian cells by retaining this executioner caspase in an inactive state.

scholarly journals Diablo Promotes Apoptosis by Removing Miha/Xiap from Processed Caspase 9

2001 ◽  
Vol 152 (3) ◽  
pp. 483-490 ◽  
Author(s):  
Paul G. Ekert ◽  
John Silke ◽  
Christine J. Hawkins ◽  
Anne M. Verhagen ◽  
David L. Vaux
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Caspase 3 ◽  
Direct Interaction ◽  
Inhibitor Of Apoptosis ◽  
Caspase 9 ◽  
Inhibitor Of Apoptosis Protein ◽  
Grim Reaper ◽  
Apoptosis Protein ◽  
Mammalian Protein

MIHA is an inhibitor of apoptosis protein (IAP) that can inhibit cell death by direct interaction with caspases, the effector proteases of apoptosis. DIABLO is a mammalian protein that can bind to IAPs and antagonize their antiapoptotic effect, a function analogous to that of the proapoptotic Drosophila molecules, Grim, Reaper, and HID. Here, we show that after UV radiation, MIHA prevented apoptosis by inhibiting caspase 9 and caspase 3 activation. Unlike Bcl-2, MIHA functioned after release of cytochrome c and DIABLO from the mitochondria and was able to bind to both processed caspase 9 and processed caspase 3 to prevent feedback activation of their zymogen forms. Once released into the cytosol, DIABLO bound to MIHA and disrupted its association with processed caspase 9, thereby allowing caspase 9 to activate caspase 3, resulting in apoptosis.

scholarly journals X-linked inhibitor of apoptosis protein and active caspase-3 expression patterns in antral follicles in the sheep ovary

Reproduction ◽  
2011 ◽  
Vol 142 (6) ◽  
pp. 855-867 ◽  
Author(s):  
Hollian R Phillipps ◽  
Ilona C Kokay ◽  
David R Grattan ◽  
Peter R Hurst
Keyword(s):  
Mrna Expression ◽  
Caspase 3 ◽  
Expression Patterns ◽  
Inhibitor Of Apoptosis ◽  
Mrna Levels ◽  
Follicular Atresia ◽  
Inhibitor Of Apoptosis Protein ◽  
Antral Follicles ◽  
Apoptosis Protein ◽  
Active Caspase

X-linked inhibitor of apoptosis protein (XIAP) interacts with caspases to inhibit their activity, thereby providing a potential mechanism for regulation of granulosa cell apoptosis occurring during follicular atresia. The aim of this study was to determine the presence and localization of XIAP mRNA and protein content in the sheep ovary and compare these expression patterns with active caspase-3 protein in the same antral follicles. Romney ewe estrous cycles (n=25) were synchronized with 2–3 Estrumate injections and ovarian tissue collected during the luteal and follicular phases of the cycle. The presence ofXIAPmRNA was confirmed by RT-PCR using laser capture microdissected ovarian cell samples.XIAPmRNA was subsequently localized byin situhybridization histochemistry and XIAP and active caspase-3 protein visualized by immunohistochemistry. In antral follicles extensive XIAP localization was evident in both granulosa and thecal cells. In contrast, mRNA expression was widespread in granulosa cells and only detected in thecal tissue from a small proportion of antral follicles. Active caspase-3 and XIAP comparative expression analysis showed positiveXIAPmRNA expression in all late luteal phase (day 14) follicles, despite varying levels of active caspase-3 protein. A proportion of follicular phase (days 15 and 16) follicles, however, showed an inverse expression relationship at the protein and mRNA levels in both granulosa and thecal tissue, as did XIAP protein in day 14 follicles. These results suggest high XIAP may prevent activation of caspase-3, thereby regulating follicular atresia in antral follicles and could potentially be utilized as a marker of follicular health.

Resistance of bone marrow-derived macrophages to apoptosis is associated with the expression of X-linked inhibitor of apoptosis protein in primary cultures of bone marrow cells

2001 ◽  
Vol 353 (2) ◽  
pp. 299-306 ◽  
Author(s):  
Hong LIN ◽  
Catheryne CHEN ◽  
Ben D.-M. CHEN
Keyword(s):  
Bone Marrow ◽  
Caspase 3 ◽  
Bone Marrow Cells ◽  
Primary Cultures ◽  
Precursor Cells ◽  
Inhibitor Of Apoptosis ◽  
Caspase 9 ◽  
Prolonged Incubation ◽  
Inhibitor Of Apoptosis Protein ◽  
Apoptosis Protein

In this study we investigated the underlying mechanisms that confer resistance on mature macrophages with the use of macrophage colony-stimulating factor (M-CSF)-induced bone marrow-derived macrophages (BMDM). In the presence of M-CSF, immature precursor cells were induced to undergo proliferation and differentiation into mature macrophages in vitro with cell morphology similar to that of tissue macrophages by day 7Ő10. Immunoblot analyses showed that bone marrow precursors express appreciable levels of caspase-3 and caspase-9 but no or very low levels of c-fms (M-CSF receptor) and the apoptosis regulators X-linked inhibitor of apoptosis protein (XIAP), c-IAP-1, Bcl-2 and Bax. The differentiation of BMDM is associated with a steady and gradual increase in the levels of c-fms, XIAP, c-IAP-1, Bcl-2 and Bax, reaching maximal levels by day 7. However, the levels of caspase-3 and caspase-9 stayed essentially unchanged even after prolonged incubation (more than 10 days) with M-CSF. Unlike bone marrow precursor cells, mature BMDM (day 7Ő10) were resistant to apoptosis induced by M-CSF depletion, which includes the activation of caspase-3 and caspase-9 and the degradation of XIAP, Bcl-2 and Bax proteins in the process. Treatment of day 7 BMDM with XIAP anti-sense oligonucleotides (oligos), but not sense oligos, partly abolished their resistance to apoptosis. By using a gel-shift assay and a specific nuclear factor κB (NF-κB) inhibitor, we demonstrated that NF-κB activity is responsible for the up-regulation of XIAP in M-CSF-treated macrophages. In addition, treatment of starved macrophages with M-CSF induced a rapid phosphorylation of Akt kinase before the activation of NF-κB. Our results showed that XIAP is one of the anti-apoptotic regulators that confer resistance on mature macrophages by M-CSF.

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