Previous Article
Molecular and Cellular Biology, May 2001, p. 3604-3608, Vol. 21, No. 10
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.10.3604-3608.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Characterization of XIAP-Deficient Mice
Helena
Harlin,1
Stephanie Birkey
Reffey,2
Colin S.
Duckett,2
Tullia
Lindsten,3 and
Craig
B.
Thompson3,*
Committee on Immunology, Department of
Medicine, University of Chicago, Chicago, Illinois
606371; Metabolism Branch, Division of
Clinical Sciences, National Cancer Institute, National Institutes of
Health, Bethesda, Maryland 208922; and
Departments of Cancer Biology and Pathology and Laboratory
Medicine, Abramson Family Cancer Research Institute, University of
Pennsylvania, Philadelphia, Pennsylvania 191043
Received 11 December 2000/Returned for modification 20 December
2000/Accepted 15 February 2001
 |
ABSTRACT |
The inhibitor of apoptosis protein (IAP) family consists of a
number of evolutionarily conserved proteins that function to inhibit
programmed cell death. X-linked IAP (XIAP) was cloned due to its
sequence homology with other family members and has previously been
shown to prevent apoptosis by binding to active caspases 3, 7, and 9 in
vitro. XIAP transcripts can be found in a variety of tissues, and the
protein levels are regulated both transcriptionally and
posttranscriptionally. To better understand the function of XIAP in
normal cells, we generated mice deficient in XIAP through homologous
gene targeting. The resulting mice were viable, and histopathological
analysis did not reveal any differences between XIAP-deficient and
wild-type mice. We were unable to detect any defects in induction of
caspase-dependent or -independent apoptosis in cells from the
gene-targeted mice. One change was observed in cells derived from
XIAP-deficient mice: the levels of c-IAP1 and c-IAP2 protein were
increased. This suggests that there exists a compensatory mechanism
that leads to upregulation of other family members when XIAP expression
is lost. The changes in c-IAP1 and c-IAP2 expression may provide
functional compensation for loss of XIAP during development or in the
induction of apoptosis.
| |
INTRODUCTION |
Viruses, in order to propagate more
efficiently, have evolved several strategies to prevent infected cells
from dying. One common mechanism utilized by viruses is to block the
host cell's apoptotic machinery, and viral genomes thus often encode
proteins that have antiapoptotic properties. The X-linked
inhibitor of apoptosis protein (XIAP), also known as
IAP-like protein or mammalian IAP homologue A, was originally
cloned as a mammalian homologue of the IAP family of viral proteins.
The IAPs are expressed in baculoviruses and function to prevent the
programmed cell death of infected cells. XIAP is ubiquitously expressed
in all normal tissues (6, 7, 16).
XIAP contains two types of conserved sequence motifs, the baculovirus
IAP repeats (BIRs) and the zinc finger-like RING finger. The BIRs are
located at the amino-terminal end of the protein, and XIAP contains
three repeats, whereas two repeats are found in the viral proteins. The
nuclear magnetic resonance structures of BIRs 2 and 3 have recently
been described (22, 23). The two BIRs have similar
characteristics and resemble a classical zinc finger. The RING finger,
believed to mediate protein-protein interactions, is situated at the
carboxyl terminus of the protein.
Cells transfected with XIAP are able to block programmed cell death in
response to a variety of apoptotic stimuli (5, 6, 29). It
has been shown that recombinant XIAP is able to specifically block the
activity of caspases 3, 7, and 9 (2, 4). In human cells,
XIAP can itself be cleaved by caspases (3) and cleavage of
endogenous XIAP can be detected in T lymphocytes undergoing apoptosis
(13). The two cleaved fragments are still able to inhibit
caspase activity (3). The cleavage occurs in the spacer region between BIR 2 and BIR 3 and correlates with the caspase-binding specificity of XIAP; the second BIR associates with caspases 3 and 7 (22, 24) while the third BIR binds caspase 9 (23).
Two closely related family members with the same overall structure as
XIAP, c-IAP1 and c-IAP2, have been identified (16, 17,
27). These proteins were cloned due to their association with
tumor necrosis factor (TNF) receptor-associated factors (TRAFs) 1 and 2 (17). The interaction of the TRAFs with the c-IAPs does not involve the RING finger domain of either the c-IAPs or the TRAFs,
but instead, the BIRs bind to the TRAF domain. Although XIAP has not
been shown to associate with any TRAF family members, the c-IAPs may
have other functions in common with XIAP. They all share the ability to
specifically inhibit active caspases 3 and 7 (4, 18), but
only XIAP is able to block caspase 9. This difference in specificity
for caspase 9 correlates with structural differences in the third BIR
between XIAP and c-IAP1 (11, 23). Four more distantly
related mammalian family members, NAIP (19), Survivin,
(1) BRUCE (9), and Livin/ML-IAP1 (15,
28), have been identified in humans. All IAP-like proteins
identified have been shown to have antiapoptotic properties in
different systems. In addition, IAP family members have been identified in Drosophila melanogaster (10),
Caenorhabditis elegans (8), and yeast
(26), demonstrating an evolutionarily conserved role for
these proteins.
Recently, some insights into the function of XIAP have been made.
Firstly, XIAP was shown to interact with transforming growth factor 
(TGF-)-activated kinase 1 binding protein 1 (TAB1) in a
Xenopus system for studying the bone morphogenic protein
(BMP) signaling pathway (30). BMPs are members of the
TGF- family, and signaling by BMP2 or BMP4 leads to downstream
activation of TGF--activated kinase 1, a mitogen-activated protein
kinase kinase kinase that is activated by TAB1. The RING finger of XIAP
is able to bind both to TAB1 and to an upstream BMP receptor (type 1), suggesting that XIAP may signal in a TGF--mediated pathway.
Secondly, XIAP can be upregulated as a result of focal adhesion kinase
overexpression (21). Focal adhesion kinase mediates
signals from integrins and neuropeptides. Finally, levels of cellular
XIAP protein appear to be carefully regulated at the
posttranscriptional level. XIAP translation has been shown to be
upregulated in response to physiological stress (12), and
XIAP can be targeted for proteasome-dependent degradation upon
proapoptotic stimuli (31).
XIAP has been shown to efficiently inhibit apoptosis in a number of in
vitro systems. To further study the role of XIAP in vivo, mice
deficient in the XIAP protein were generated by homologous gene
targeting. Despite complete lack of XIAP expression, the XIAP-deficient
mice were born at the expected Mendelian frequency, had no obvious
physical or histological defects, and had normal life spans. No obvious
defects in programmed cell death were seen after the induction of
apoptosis using a variety of stimuli.
| |
MATERIALS AND METHODS |
Targeting strategy.
A 0.7-kb PstI-NcoI
fragment containing the first two BIRs of human xiap was
used to screen a phage library (Lambda FIX II; Stratagene Cloning
Systems, La Jolla, Calif.) derived from 129/SvJ mice. The resulting
genomic clones were mapped by restriction digest analysis, Southern
blotting, and sequencing. The genomic organization of mouse
xiap has also been published (7). A 2.2-kb BamHI-XbaI fragment located 5' of exon 1 and an
8.3-kb HindIII-HindIII fragment
containing exons 2 to 6 were cut out from the same phage preparation
and subcloned into the pPNT vector (25). Upon
linearization, the resulting targeting construct contained the
phosphoglycerate kinase (PGK)-neor cassette in a
transcriptional orientation opposite that of the XIAP gene, in between
the two subcloned genomic fragments that were flanked on one side by
the PGK-thymidine kinase (TK) cassette.
Generation of XIAP-deficient mice.
The electroporation,
culture, and selection of neor, TK-negative
embryonic stem (ES) cells were as previously described
(20). The resulting expanded ES cell clones were screened
by Southern blot analysis of BglII-digested genomic DNA
isolated from each clone. The 0.2-kb BamHI-EcoRI
probe used to identify homologously recombined ES cell clones is shown
in Fig. 1A.
ES cells from three independent clones were injected into C57BL/6
blastocysts, and chimeric mice with a large contribution of targeted ES
cells were identified due to their mainly agouti coat color. Largely
agouti chimeras were bred to C57BL/6 females, and the resulting
F1 progeny were screened by Southern blot analysis of tail
DNA to determine their genotype. Mice with germ line transmission of a
targeted XIAP allele were intercrossed to generate XIAP-deficient mice.
Western and Northern blot analysis.
Protein lysates were
made as previously described (5). For the TNF-treated
samples, confluent mouse embryonic fibroblasts were treated with 200 U
of human TNF-
(Boehringer-Mannheim, Indianapolis, Ind.)/ml for
4 h at 37°C before the cells were lysed. Protein concentrations
were determined by Bradford assay (Bio-Rad Laboratories, Hercules,
Calif.). Protein samples (20 µg [see Fig. 2] or 5 µg [see Fig.
4]) were resolved by sodium dodecyl sulfate 4 to 12% gradient gel
electrophoresis and then transferred to nitrocellulose membranes by
electrophoretic blotting (Novex; Invitrogen, Carlsbad, Calif.). XIAP
protein was detected using a monoclonal antibody raised against a
protein fragment spanning human XIAP amino acids 268 to 426, containing
the third BIR and the spacer region before the RING finger (catalog no.
H59520; Transduction Laboratories, Lexington, Ky.). c-IAP1 protein was
detected using a monoclonal antibody from the F39 hybridoma, which was
raised against a fragment of c-IAP1 lacking the first BIR and which
specifically recognizes c-IAP1. c-IAP2 protein was detected using a
polyclonal antibody raised against a peptide containing amino acids 507 to 524 of human c-IAP2 (R&D Systems Inc., Minneapolis, Minn.). Relative amounts of protein were visualized using an antibody directed against
-tubulin (BD Pharmingen, San Diego, Calif.). Antibody detection was
performed using an enhanced chemiluminescence detection system
(Amersham-Pharmacia, Piscataway, N.J.).
Total RNA was purified from wild-type (WT) and knockout (KO) mice using
TRIzol (Gibco BRL, Grand Island, N.Y.). The RNA was
equalized as
previously described (
14), and the concentration
was later
determined by spectrophotometric analysis. Approximately
5 µg of
total RNA was used for each sample. The samples were loaded
on an
agarose gel, electrophoresed, and blotted as previously
described
(
14). XIAP transcripts were detected using either
a 0.8-kb
XbaI-
NcoI probe containing exon 1 or a 0.5-kb
HindIII-
HindIII
probe containing the RING
domain (exon 6). The relative amounts
of RNA were visualized using an
end-labeled 5S RNA
probe.
Induction of cell death. (i) Fas-mediated apoptosis.
Single
cell suspensions from the thymus of WT or XIAP-deficient mice were
plated on 24-well plates at 106 cells/well. Anti-Fas
antibody (Jo2) or isotype control antibody (BD Pharmingen) was added to
a final concentration of 1 µg/ml. Apoptotic CD4+
CD8+ cells were identified by staining the cells with
fluorescein isothiocyanate-coupled anti-CD4 and phycoerythrin-coupled
anti-CD8 antibodies (BD Pharmingen) in addition to propidium iodide
(PI). The fluorescence-activated cell sorter (FACS) profiles were gated on CD4+ CD8+ cells, and the percentage of
PI+ cells was determined.
(ii) UV irradiation and oligomycin-induced apoptosis.
Mouse
embryonic fibroblasts were generated from WT or XIAP-deficient embryos.
Fifteen-day-old embryos were dissected away from surrounding
extraembryonic membranes. Heads, tails, limbs, hearts, and livers were
removed. Each embryo was cut into small pieces and incubated with
rotation in 0.05% trypsin-EDTA (3 ml/embryo) (Gibco BRL) overnight at
4°C. The embryos were placed at 37°C for 30 min, broken up by
pipetting, and then left to sediment for a few minutes. Cells still in
suspension were collected, and sedimented material was treated twice
more with fresh trypsin-EDTA solution for 30 min at 37°C, with cells
in suspension collected after each incubation. The pooled cells were
plated on tissue culture dishes and fibroblasts were allowed to grow
out in Dulbecco's minimal essential medium (21).
Plated fibroblasts of equal degrees of confluency were UV irradiated
for 30 s at 254 nm using a UV Stratalinker 2400 (Stratagene)
(corresponding to 1,200 J m
2) or treated with 50 µg of
oligomycin (Sigma, St. Louis, Mo.)/ml.
After 24 h, the percentage
of apoptotic cells was determined by
PI staining and FACS
analysis.
| |
RESULTS AND DISCUSSION |
Gene targeting and generation of XIAP-deficient mice.
The XIAP
gene was disrupted by homologous gene targeting. Three independent ES
cell lines were used to generate XIAP-deficient mice, using the
targeting construct shown in Fig. 1A.
This targeting strategy was chosen because it results in the deletion
of exon 1, which is the largest of the six coding exons and contains
the first two BIRs and half of the third. Thus, even if a partial transcript had been expressed in the targeted cells, the truncated protein would presumably not be functional. Figure 1B shows an example
of Southern blot analysis of DNA from the offspring of breedings set up
to generate XIAP-deficient mice. The probe used, shown in Fig. 1A,
recognizes a 4.0-kb fragment from the WT allele and a 3.2-kb fragment
from the targeted allele.
View larger version (29K):
[in this window]
[in a new window]
|
FIG. 1.
Generation of XIAP-deficient mice by gene targeting. (A)
Schematic representation of the targeting strategy used to disrupt the
XIAP gene. The locations of exons 1 and 6 are shown. Exons 2 to 5 are
contained within the 8.3-kb
HindIII-HindIII fragment (not shown). The
targeting construct replaces the coding sequence of exon 1 with the
neomycin resistance gene, in the opposite transcriptional orientation.
The sequence used as a probe to screen for homologously recombined DNA
is shown. B (BglII) and H (HindIII) sites are
shown for the genomic and targeted DNA. (B) Southern blot analysis of
BglII-digested tail DNA from targeted mice. The WT allele is
4.0 kb, and the targeted allele is 3.2 kb. The blots were probed with
the 0.2-kb BamHI-EcoRI fragment shown in panel
A.
|
|
Mouse embryonic fibroblasts from mice that lack the WT allele had no
detectable XIAP protein (Fig.
2A). The
anti-XIAP antibody
recognizes an epitope contained within the
C-terminal part of
the protein, and the DNA encoding this part was not
deleted by
the targeting construct, so the antibody should detect any
residual
XIAP protein. The Northern blot in Fig.
2B was hybridized with
either a probe derived from exon 1 or a probe derived from exon
6, which is still present in the targeted allele. The XIAP-deficient
RNA
samples showed no distinct transcripts. We concluded that
the targeting
strategy used completely abolishes XIAP expression
in the targeted
mice.
View larger version (56K):
[in this window]
[in a new window]
|
FIG. 2.
Targeted mice have no detectable XIAP protein or mRNA.
(A) Western blot analysis of lysate from WT or XIAP-deficient (KO)
embryonic fibroblasts. Lysate from a hybridoma lacking XIAP expression
(F39) was used as a negative control. Lysate from 293 cells served as a
positive control. Molecular mass standards, in kilodaltons, are
indicated on the left. (B) Northern blot analysis of RNA from WT or
XIAP-deficient (KO) tissues. The top blot was probed with a fragment
from exon 1, which is deleted in the KO tissues. The bottom blot shows
a duplicate blot probed with a fragment from exon 6, which is not
affected by XIAP gene targeting. The loading of RNA was verified using
5S rRNA.
|
|
XIAP-deficient mice were born at the expected Mendelian ratio, bred
normally, and had no overt physical or behavioral abnormalities.
Histological examination of selected tissues (heart, kidney, liver,
lung, and brain) failed to show any differences between WT and
XIAP KO
mice (data not shown). The mice had life spans of greater
than 1 year
and did not succumb to disease, even when kept in
a non-barrier type
animal facility. The mice had normal numbers
of B cells as well as
CD4
+ and CD8
+ T cells, as evidenced by FACS
staining of thymus, spleen, and
lymph node cells. In a variety of
immunological assays, shown
in Table
1,
no significant differences could be observed between
WT and
XIAP-deficient mice. For these analyses and all others
reported here,
the XIAP KO mice were of a mixed genetic background
between the
129S/SvJ and C57BL/6 strains. The WT mice used in
each assay were
littermates of the KO mice analyzed.
Induction of apoptosis occurs normally in XIAP-deficient mice.
Since XIAP can act as an inhibitor of apoptosis in a variety of
systems, we investigated whether programmed cell death was affected in
the XIAP-deficient animals. Fas-mediated apoptosis occurs through
direct activation of caspase 8, which in turn activates caspases 3 and
7, two of the caspases that XIAP has been shown to inhibit in vitro.
Fas-mediated apoptosis of thymocytes was analyzed (Fig.
3A). Treatment with anti-Fas monoclonal
antibody in vitro induced similar levels of apoptosis in both WT and
XIAP KO CD4+ CD8+ thymocytes, indicating that
Fas-mediated apoptosis was not affected by loss of XIAP in this system.
Since the two reports of endogenous XIAP being cleaved by caspases used
Jurkat T cells or T lymphocytes to study this phenomenon (3,
13), thymocytes should be a valid cell type for detecting any
abnormal regulation of apoptosis in the XIAP-deficient cells.
View larger version (22K):
[in this window]
[in a new window]
|
FIG. 3.
Apoptosis occurs normally in XIAP-deficient mice. (A)
Fas-mediated apoptosis of double-positive (CD4+
CD8+) thymocytes. WT or XIAP-deficient thymocytes were
treated with either isotype control (ctrl) or anti-Fas (-Fas)
antibody. The percentage of apoptotic (PI+) cells was
determined at the indicated time points. Cells from one WT and one KO
mouse were plated in triplicate, and average values are shown along
with the standard deviation for each triplicate sample. The data are
representative of three separate experiments. (B) Caspase-dependent or
-independent apoptosis. Embryonic fibroblasts were left untreated
(ctrl) or treated with either UV irradiation or oligomycin. The
percentage of apoptotic cells was determined at 24 h after
treatment. WT and KO cells were plated in triplicate, and average
values are shown along with the standard deviation for each triplicate
sample. The data are representative of two separate experiments.
|
|
We next investigated whether UV irradiation- and oligomycin-induced
apoptosis was affected in XIAP-deficient cells. Caspase
9-deficient
embryonic fibroblasts are resistant to UV irradiation-induced
apoptosis, and thus activation of this caspase ought to be required
for
UV-mediated apoptosis in this cell type. Caspase 9 activity
can be
inhibited by XIAP in vitro, and XIAP protein is present
in embryonic
fibroblasts (Fig.
2A). In contrast, oligomycin induces
cell death in a
caspase-independent manner, and this type of death-inducing
stimulus
would presumably not be affected by loss of XIAP. Embryonic
fibroblasts
were untreated, UV irradiated, or treated with oligomycin.
No
differences in the ability to undergo apoptosis were observed
between
WT and XIAP-deficient cells following UV irradiation at
1,200 J
m
2 or treatment with 50 µg of oligomycin/ml (Fig.
3B).
Similar results
were obtained using various doses of UV irradiation and
concentrations
of oligomycin (data not
shown).
To characterize the XIAP-deficient mice further, we performed a number
of assays focusing on a potential role for XIAP in
the immune system
and in particular in response to apoptotic stimulation.
In numerous
assays, cells from these mice responded in a manner
indistinguishable
from WT cells to both pro- and antiapoptotic
stimuli (Table
1).
Levels of c-IAP1 and c-IAP2 are increased in XIAP-deficient
cells.
Since several mammalian homologues have been identified, it
is possible that other family members are able to compensate for the
lack of XIAP. To address this issue, we investigated the levels of
c-IAP1 and c-IAP2 protein found in WT or XIAP-deficient embryonic fibroblasts that were either untreated or treated with TNF- for 4 h. The tubulin levels for each sample were also determined, as a
control for protein loading. We noticed a consistent increase of c-IAP1
and c-IAP2 levels in the XIAP-deficient cells compared to the WT cells
(Fig. 4), but no concomitant increase in
tubulin expression was noticed. The levels of XIAP and c-IAP1 were not affected by TNF treatment, whereas the level of c-IAP2 decreased upon
treatment. This result suggests that one potential explanation for the
lack of a phenotype in XIAP-deficient mice is due to compensation by
other family members.
View larger version (22K):
[in this window]
[in a new window]
|
FIG. 4.
Levels of c-IAP1 and c-IAP2 proteins are upregulated in
XIAP-deficient cells. Western blot analysis of lysate from WT or
XIAP-deficient (KO) embryonic fibroblasts. The cells were either
untreated or stimulated with 200 U of human TNF-/ml for 4 h.
Gels were loaded in parallel, and the resulting blots were probed with
antibodies directed against XIAP (A), c-IAP1 (B), or c-IAP2 (C). The
blots were stripped and reprobed with an antibody against -tubulin,
shown at the bottom of each panel. Molecular mass standards, in
kilodaltons, are indicated on the left.
|
|
It is also possible that we have not found the situation in which XIAP
is critically important in preventing apoptosis in
vivo, either because
it is the only IAP family member expressed
or because XIAP can function
in a manner distinct from other family
members.
In conclusion, despite a seemingly important role for XIAP in the
inhibition of apoptosis in a variety of in vitro systems,
XIAP-deficient mice do not have any obvious defects in development
or
in the regulation of
apoptosis.
| |
ACKNOWLEDGMENTS |
This work was supported in part by grants from the National
Institutes of Health.
Andras Nagy, Reka Nagy, and Wanda Abramow-Newerly are gratefully
acknowledged for providing the RI ES cell line. We thank Daniel R. Brown for technical assistance with the Leishmania major studies and Maria-Luisa Alegre for critical review of the manuscript.
| |
FOOTNOTES |
*
Corresponding author. Mailing address: Abramson Family
Cancer Research Institute, Room 450, BRB II/III, 421 Curie Blvd.,
Philadelphia, PA 19104-6160. Phone: (215) 746-5515. Fax: (215)
746-5511. E-mail: craig{at}mail.med.upenn.edu.
| |
REFERENCES |
| 1.
|
Ambrosini, G.,
C. Adida, and D. C. Altieri.
1997.
A novel anti-apoptosis gene, survivin, expressed in cancer and lymphoma.
Nat. Med.
3:917-921[CrossRef][Medline].
|
| 2.
|
Datta, R.,
E. Oki,
K. Endo,
V. Biedermann,
J. Ren, and D. Kufe.
2000.
XIAP regulates DNA damage-induced apoptosis downstream of caspase-9 cleavage.
J. Biol. Chem.
275:31733-31738[Abstract/Free Full Text].
|
| 3.
|
Deveraux, Q. L.,
E. Leo,
H. R. Stennicke,
K. Welsh,
G. S. Salvesen, and J. C. Reed.
1999.
Cleavage of human inhibitor of apoptosis protein XIAP results in fragments with distinct specificities for caspases.
EMBO J.
18:5242-5251[CrossRef][Medline].
|
| 4.
|
Deveraux, Q. L.,
R. Takahashi,
G. S. Salvesen, and J. C. Reed.
1997.
X-linked IAP is a direct inhibitor of cell-death proteases.
Nature
388:300-304[CrossRef][Medline].
|
| 5.
|
Duckett, C. S.,
F. Li,
Y. Wang,
K. J. Tomaselli,
C. B. Thompson, and R. C. Armstrong.
1998.
Human IAP-like protein regulates programmed cell death downstream of Bcl-xL and cytochrome c.
Mol. Cell. Biol.
18:608-615[Abstract/Free Full Text].
|
| 6.
|
Duckett, C. S.,
V. E. Nava,
R. W. Gedrich,
R. J. Clem,
J. L. Van Dongen,
M. C. Gilfillan,
H. Shiels,
J. M. Hardwick, and C. B. Thompson.
1996.
A conserved family of cellular genes related to the baculovirus iap gene and encoding apoptosis inhibitors.
EMBO J.
15:2685-2694[Medline].
|
| 7.
|
Farahani, R.,
W. G. Fong,
R. G. Korneluk, and A. E. MacKenzie.
1997.
Genomic organization and primary characterization of miap-3: the murine homologue of human X-linked IAP.
Genomics
42:514-518[CrossRef][Medline].
|
| 8.
|
Fraser, A. G.,
C. James,
G. I. Evan, and M. O. Hengartner.
1999.
Caenorhabditis elegans inhibitor of apoptosis protein (IAP) homologue BIR-1 plays a conserved role in cytokinesis.
Curr. Biol.
9:292-301[CrossRef][Medline].
|
| 9.
|
Hauser, H. P.,
M. Bardroff,
G. Pyrowolakis, and S. Jentsch.
1998.
A giant ubiquitin-conjugating enzyme related to IAP apoptosis inhibitors.
J. Cell Biol.
141:1415-1422[Abstract/Free Full Text].
|
| 10.
|
Hay, B. A.,
D. A. Wassarman, and G. M. Rubin.
1995.
Drosophila homologs of baculovirus inhibitor of apoptosis proteins function to block cell death.
Cell
83:1253-1262[CrossRef][Medline].
|
| 11.
|
Hinds, M. G.,
R. S. Norton,
D. L. Vaux, and C. L. Day.
1999.
Solution structure of a baculoviral inhibitor of apoptosis (IAP) repeat.
Nat. Struct. Biol.
6:648-651[CrossRef][Medline].
|
| 12.
|
Holcik, M.,
C. Yeh,
R. G. Korneluk, and T. Chow.
2000.
Translational upregulation of X-linked inhibitor of apoptosis (XIAP) increases resistance to radiation induced cell death.
Oncogene
19:4174-4177[CrossRef][Medline].
|
| 13.
|
Johnson, D. E.,
B. R. Gastman,
E. Wieckowski,
G. Q. Wang,
A. Amoscato,
S. M. Delach, and H. Rabinowich.
2000.
Inhibitor of apoptosis protein hILP undergoes caspase-mediated cleavage during T lymphocyte apoptosis.
Cancer Res.
60:1818-1823[Abstract/Free Full Text].
|
| 14.
|
June, C. H.,
J. A. Ledbetter,
M. M. Gillespie,
T. Lindsten, and C. B. Thompson.
1987.
T-cell proliferation involving the CD28 pathway is associated with cyclosporine-resistant interleukin 2 gene expression.
Mol. Cell. Biol.
7:4472-4481[Abstract/Free Full Text].
|
| 15.
|
Kasof, G. M., and B. C. Gomes.
2001.
Livin, a novel inhibitor of apoptosis protein family member.
J. Biol. Chem.
276:3238-3246[Abstract/Free Full Text].
|
| 16.
|
Liston, P.,
N. Roy,
K. Tamai,
C. Lefebvre,
S. Baird,
G. Cherton-Horvat,
R. Farahani,
M. McLean,
J. E. Ikeda,
A. MacKenzie, and R. G. Korneluk.
1996.
Suppression of apoptosis in mammalian cells by NAIP and a related family of IAP genes.
Nature
379:349-353[CrossRef][Medline].
|
| 17.
|
Rothe, M.,
M. G. Pan,
W. J. Henzel,
T. M. Ayres, and D. V. Goeddel.
1995.
The TNFR2-TRAF signaling complex contains two novel proteins related to baculoviral inhibitor of apoptosis proteins.
Cell
83:1243-1252[CrossRef][Medline].
|
| 18.
|
Roy, N.,
Q. L. Deveraux,
R. Takahashi,
G. S. Salvesen, and J. C. Reed.
1997.
The c-IAP-1 and c-IAP-2 proteins are direct inhibitors of specific caspases.
EMBO J.
16:6914-6925[CrossRef][Medline].
|
| 19.
|
Roy, N.,
M. S. Mahadevan,
M. McLean,
G. Shutler,
Z. Yaraghi,
R. Farahani,
S. Baird,
A. Besner-Johnston,
C. Lefebvre,
X. Kang, et al.
1995.
The gene for neuronal apoptosis inhibitory protein is partially deleted in individuals with spinal muscular atrophy.
Cell
80:167-178[CrossRef][Medline].
|
| 20.
|
Shiels, H.,
X. Li,
P. T. Schumacker,
E. Maltepe,
P. A. Padrid,
A. Sperling,
C. B. Thompson, and T. Lindsten.
2000.
TRAF4 deficiency leads to tracheal malformation with resulting alterations in air flow to the lungs.
Am. J. Pathol.
157:679-688[Abstract/Free Full Text].
|
| 21.
|
Sonoda, Y.,
Y. Matsumoto,
M. Funakoshi,
D. Yamamoto,
S. K. Hanks, and T. Kasahara.
2000.
Anti-apoptotic role of focal adhesion kinase (FAK). Induction of inhibitor-of-apoptosis proteins and apoptosis suppression by the overexpression of FAK in a human leukemic cell line, HL-60.
J. Biol. Chem.
275:16309-16315[Abstract/Free Full Text].
|
| 22.
|
Sun, C.,
M. Cai,
A. H. Gunasekera,
R. P. Meadows,
H. Wang,
J. Chen,
H. Zhang,
W. Wu,
N. Xu,
S. C. Ng, and S. W. Fesik.
1999.
NMR structure and mutagenesis of the inhibitor-of-apoptosis protein XIAP.
Nature
401:818-822[CrossRef][Medline].
|
| 23.
|
Sun, C.,
M. Cai,
R. P. Meadows,
N. Xu,
A. H. Gunasekera,
J. Herrmann,
J. C. Wu, and S. W. Fesik.
2000.
NMR structure and mutagenesis of the third Bir domain of the inhibitor of apoptosis protein XIAP.
J. Biol. Chem.
275:33777-33781[Abstract/Free Full Text].
|
| 24.
|
Takahashi, R.,
Q. Deveraux,
I. Tamm,
K. Welsh,
N. Assa-Munt,
G. S. Salvesen, and J. C. Reed.
1998.
A single BIR domain of XIAP sufficient for inhibiting caspases.
J. Biol. Chem.
273:7787-7790[Abstract/Free Full Text].
|
| 25.
|
Tybulewicz, V. L.,
C. E. Crawford,
P. K. Jackson,
R. T. Bronson, and R. C. Mulligan.
1991.
Neonatal lethality and lymphopenia in mice with a homozygous disruption of the c-abl proto-oncogene.
Cell
65:1153-1163[CrossRef][Medline].
|
| 26.
|
Uren, A. G.,
T. Beilharz,
M. J. O'Connell,
S. J. Bugg,
R. van Driel,
D. L. Vaux, and T. Lithgow.
1999.
Role for yeast inhibitor of apoptosis (IAP)-like proteins in cell division.
Proc. Natl. Acad. Sci. USA
96:10170-10175[Abstract/Free Full Text].
|
| 27.
|
Uren, A. G.,
M. Pakusch,
C. J. Hawkins,
K. L. Puls, and D. L. Vaux.
1996.
Cloning and expression of apoptosis inhibitory protein homologs that function to inhibit apoptosis and/or bind tumor necrosis factor receptor-associated factors.
Proc. Natl. Acad. Sci. USA
93:4974-4978[Abstract/Free Full Text].
|
| 28.
|
Vucic, D.,
H. R. Stennicke,
M. T. Pisabarro,
G. S. Salvesen, and V. M. Dixit.
2000.
ML-IAP, a novel inhibitor of apoptosis that is preferentially expressed in human melanomas.
Curr. Biol.
10:1359-1366[CrossRef][Medline].
|
| 29.
|
Xu, D.,
Y. Bureau,
D. C. McIntyre,
D. W. Nicholson,
P. Liston,
Y. Zhu,
W. G. Fong,
S. J. Crocker,
R. G. Korneluk, and G. S. Robertson.
1999.
Attenuation of ischemia-induced cellular and behavioral deficits by X chromosome-linked inhibitor of apoptosis protein overexpression in the rat hippocampus.
J. Neurosci.
19:5026-5033[Abstract/Free Full Text].
|
| 30.
|
Yamaguchi, K.,
S. Nagai,
J. Ninomiya-Tsuji,
M. Nishita,
K. Tamai,
K. Irie,
N. Ueno,
E. Nishida,
H. Shibuya, and K. Matsumoto.
1999.
XIAP, a cellular member of the inhibitor of apoptosis protein family, links the receptors to TAB1-TAK1 in the BMP signaling pathway.
EMBO J.
18:179-187[CrossRef][Medline].
|
| 31.
|
Yang, Y.,
S. Fang,
J. P. Jensen,
A. M. Weissman, and J. D. Ashwell.
2000.
Ubiquitin protein ligase activity of IAPs and their degradation in proteasomes in response to apoptotic stimuli.
Science
288:874-877[Abstract/Free Full Text].
|
Molecular and Cellular Biology, May 2001, p. 3604-3608, Vol. 21, No. 10
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.10.3604-3608.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Boehme, K. W., Guglielmi, K. M., Dermody, T. S.
(2009). Reovirus nonstructural protein {sigma}1s is required for establishment of viremia and systemic dissemination. Proc. Natl. Acad. Sci. USA
106: 19986-19991
[Abstract]
[Full Text]
-
Neil, J. R., Tian, M., Schiemann, W. P.
(2009). X-linked Inhibitor of Apoptosis Protein and Its E3 Ligase Activity Promote Transforming Growth Factor-{beta}-mediated Nuclear Factor-{kappa}B Activation during Breast Cancer Progression. J. Biol. Chem.
284: 21209-21217
[Abstract]
[Full Text]
-
Heazell, A. E. P., Buttle, H. R., Baker, P. N., Crocker, I. P.
(2008). Altered Expression of Regulators of Caspase Activity within Trophoblast of Normal Pregnancies and Pregnancies Complicated by Preeclampsia. Reproductive Sciences
15: 1034-1043
[Abstract]
-
Schile, A. J., Garcia-Fernandez, M., Steller, H.
(2008). Regulation of apoptosis by XIAP ubiquitin-ligase activity. Genes Dev.
22: 2256-2266
[Abstract]
[Full Text]
-
Glasgow, E., Mishra, L.
(2008). Transforming growth factor-{beta} signaling and ubiquitinators in cancer. Endocr Relat Cancer
15: 59-72
[Abstract]
[Full Text]
-
Wilkinson, J. C., Wilkinson, A. S., Galban, S., Csomos, R. A., Duckett, C. S.
(2008). Apoptosis-Inducing Factor Is a Target for Ubiquitination through Interaction with XIAP. Mol. Cell. Biol.
28: 237-247
[Abstract]
[Full Text]
-
Ho, A. T., Li, Q. H., Okada, H., Mak, T. W., Zacksenhaus, E.
(2007). XIAP Activity Dictates Apaf-1 Dependency for Caspase 9 Activation. Mol. Cell. Biol.
27: 5673-5685
[Abstract]
[Full Text]
-
Zwerts, F., Lupu, F., De Vriese, A., Pollefeyt, S., Moons, L., Altura, R. A., Jiang, Y., Maxwell, P. H., Hill, P., Oh, H., Rieker, C., Collen, D., Conway, S. J., Conway, E. M.
(2007). Lack of endothelial cell survivin causes embryonic defects in angiogenesis, cardiogenesis, and neural tube closure. Blood
109: 4742-4752
[Abstract]
[Full Text]
-
Leulier, F., Lhocine, N., Lemaitre, B., Meier, P.
(2006). The Drosophila Inhibitor of Apoptosis Protein DIAP2 Functions in Innate Immunity and Is Essential To Resist Gram-Negative Bacterial Infection. Mol. Cell. Biol.
26: 7821-7831
[Abstract]
[Full Text]
-
Shen, H.-M., Pervaiz, S.
(2006). TNF receptor superfamily-induced cell death: redox-dependent execution. FASEB J.
20: 1589-1598
[Abstract]
[Full Text]
-
Donath, S., Li, P., Willenbockel, C., Al-Saadi, N., Gross, V., Willnow, T., Bader, M., Martin, U., Bauersachs, J., Wollert, K. C., Dietz, R., von Harsdorf, R., on behalf of the German Heart Failure Network,
(2006). Apoptosis Repressor With Caspase Recruitment Domain Is Required for Cardioprotection in Response to Biomechanical and Ischemic Stress. Circulation
113: 1203-1212
[Abstract]
[Full Text]
-
Twiddy, D., Cohen, G. M., MacFarlane, M., Cain, K.
(2006). Caspase-7 Is Directly Activated by the ~700-kDa Apoptosome Complex and Is Released as a Stable XIAP-Caspase-7 ~200-kDa Complex. J. Biol. Chem.
281: 3876-3888
[Abstract]
[Full Text]
-
Mareninova, O. A., Sung, K.-F., Hong, P., Lugea, A., Pandol, S. J., Gukovsky, I., Gukovskaya, A. S.
(2006). Cell Death in Pancreatitis: CASPASES PROTECT FROM NECROTIZING PANCREATITIS. J. Biol. Chem.
281: 3370-3381
[Abstract]
[Full Text]
-
Conte, D., Holcik, M., Lefebvre, C. A., LaCasse, E., Picketts, D. J., Wright, K. E., Korneluk, R. G.
(2006). Inhibitor of Apoptosis Protein cIAP2 Is Essential for Lipopolysaccharide-Induced Macrophage Survival. Mol. Cell. Biol.
26: 699-708
[Abstract]
[Full Text]
-
Potts, M. B., Vaughn, A. E., McDonough, H., Patterson, C., Deshmukh, M.
(2005). Reduced Apaf-1 levels in cardiomyocytes engage strict regulation of apoptosis by endogenous XIAP. JCB
171: 925-930
[Abstract]
[Full Text]
-
Kaur, S., Wang, F., Venkatraman, M., Arsura, M.
(2005). X-linked Inhibitor of Apoptosis (XIAP) Inhibits c-Jun N-terminal Kinase 1 (JNK1) Activation by Transforming Growth Factor {beta}1 (TGF-{beta}1) through Ubiquitin-mediated Proteosomal Degradation of the TGF-{beta}1-activated Kinase 1 (TAK1). J. Biol. Chem.
280: 38599-38608
[Abstract]
[Full Text]
-
Silke, J., Kratina, T., Chu, D., Ekert, P. G., Day, C. L., Pakusch, M., Huang, D. C. S., Vaux, D. L.
(2005). Determination of cell survival by RING-mediated regulation of inhibitor of apoptosis (IAP) protein abundance. Proc. Natl. Acad. Sci. USA
102: 16182-16187
[Abstract]
[Full Text]
-
Carter, B. Z., Gronda, M., Wang, Z., Welsh, K., Pinilla, C., Andreeff, M., Schober, W. D., Nefzi, A., Pond, G. R., Mawji, I. A., Houghten, R. A., Ostresh, J., Brandwein, J., Minden, M. D., Schuh, A. C., Wells, R. A., Messner, H., Chun, K., Reed, J. C., Schimmer, A. D.
(2005). Small-molecule XIAP inhibitors derepress downstream effector caspases and induce apoptosis of acute myeloid leukemia cells. Blood
105: 4043-4050
[Abstract]
[Full Text]
-
Muro, I., Means, J. C., Clem, R. J.
(2005). Cleavage of the Apoptosis Inhibitor DIAP1 by the Apical Caspase DRONC in Both Normal and Apoptotic Drosophila Cells. J. Biol. Chem.
280: 18683-18688
[Abstract]
[Full Text]
-
Kornbluth, S., White, K.
(2005). Apoptosis in Drosophila: neither fish nor fowl (nor man, nor worm). J. Cell Sci.
118: 1779-1787
[Abstract]
[Full Text]
-
Conze, D. B., Albert, L., Ferrick, D. A., Goeddel, D. V., Yeh, W.-C., Mak, T., Ashwell, J. D.
(2005). Posttranscriptional Downregulation of c-IAP2 by the Ubiquitin Protein Ligase c-IAP1 In Vivo. Mol. Cell. Biol.
25: 3348-3356
[Abstract]
[Full Text]
-
Ren, J., Shi, M., Liu, R., Yang, Q.-H., Johnson, T., Skarnes, W. C., Du, C.
(2005). The Birc6 (Bruce) gene regulates p53 and the mitochondrial pathway of apoptosis and is essential for mouse embryonic development. Proc. Natl. Acad. Sci. USA
102: 565-570
[Abstract]
[Full Text]
-
Schimmer, A. D., Dalili, S.
(2005). Targeting the IAP Family of Caspase Inhibitors as an Emerging Therapeutic Strategy. ASH Education Book
2005: 215-219
[Abstract]
[Full Text]
-
Martins, L. M., Morrison, A., Klupsch, K., Fedele, V., Moisoi, N., Teismann, P., Abuin, A., Grau, E., Geppert, M., Livi, G. P., Creasy, C. L., Martin, A., Hargreaves, I., Heales, S. J., Okada, H., Brandner, S., Schulz, J. B., Mak, T., Downward, J.
(2004). Neuroprotective Role of the Reaper-Related Serine Protease HtrA2/Omi Revealed by Targeted Deletion in Mice. Mol. Cell. Biol.
24: 9848-9862
[Abstract]
[Full Text]
-
Wang, Z., Cuddy, M., Samuel, T., Welsh, K., Schimmer, A., Hanaii, F., Houghten, R., Pinilla, C., Reed, J. C.
(2004). Cellular, Biochemical, and Genetic Analysis of Mechanism of Small Molecule IAP Inhibitors. J. Biol. Chem.
279: 48168-48176
[Abstract]
[Full Text]
-
Lotz, K., Pyrowolakis, G., Jentsch, S.
(2004). BRUCE, a Giant E2/E3 Ubiquitin Ligase and Inhibitor of Apoptosis Protein of the trans-Golgi Network, Is Required for Normal Placenta Development and Mouse Survival. Mol. Cell. Biol.
24: 9339-9350
[Abstract]
[Full Text]
-
Lindholm, D., Arumae, U.
(2004). Cell differentiation: reciprocal regulation of Apaf-1 and the inhibitor of apoptosis proteins. JCB
167: 193-195
[Abstract]
[Full Text]
-
Wright, K. M., Linhoff, M. W., Potts, P. R., Deshmukh, M.
(2004). Decreased apoptosome activity with neuronal differentiation sets the threshold for strict IAP regulation of apoptosis. JCB
167: 303-313
[Abstract]
[Full Text]
-
Schimmer, A. D.
(2004). Inhibitor of Apoptosis Proteins: Translating Basic Knowledge into Clinical Practice. Cancer Res.
64: 7183-7190
[Abstract]
[Full Text]
-
Papa, S., Zazzeroni, F., Pham, C. G., Bubici, C., Franzoso, G.
(2004). Linking JNK signaling to NF-{kappa}B: a key to survival. J. Cell Sci.
117: 5197-5208
[Abstract]
[Full Text]
-
Dohi, T., Okada, K., Xia, F., Wilford, C. E., Samuel, T., Welsh, K., Marusawa, H., Zou, H., Armstrong, R., Matsuzawa, S.-i., Salvesen, G. S., Reed, J. C., Altieri, D. C.
(2004). An IAP-IAP Complex Inhibits Apoptosis. J. Biol. Chem.
279: 34087-34090
[Abstract]
[Full Text]
-
Creagh, E. M., Murphy, B. M., Duriez, P. J., Duckett, C. S., Martin, S. J.
(2004). Smac/Diablo Antagonizes Ubiquitin Ligase Activity of Inhibitor of Apoptosis Proteins. J. Biol. Chem.
279: 26906-26914
[Abstract]
[Full Text]
-
Cummins, J. M., Kohli, M., Rago, C., Kinzler, K. W., Vogelstein, B., Bunz, F.
(2004). X-Linked Inhibitor of Apoptosis Protein (XIAP) Is a Nonredundant Modulator of Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)- Mediated Apoptosis in Human Cancer Cells. Cancer Res.
64: 3006-3008
[Abstract]
[Full Text]
-
Zhang, Y., Chen, F.
(2004). Reactive Oxygen Species (ROS), Troublemakers between Nuclear Factor-{kappa}B (NF-{kappa}B) and c-Jun NH2-terminal Kinase (JNK). Cancer Res.
64: 1902-1905
[Abstract]
[Full Text]
-
Silke, J., Kratina, T., Ekert, P. G., Pakusch, M., Vaux, D. L.
(2004). Unlike Diablo/smac, Grim Promotes Global Ubiquitination and Specific Degradation of X Chromosome-linked Inhibitor of Apoptosis (XIAP) and Neither Cause Apoptosis. J. Biol. Chem.
279: 4313-4321
[Abstract]
[Full Text]
-
Carter, B. Z., Kornblau, S. M., Tsao, T., Wang, R.-Y., Schober, W. D., Milella, M., Sung, H.-G., Reed, J. C., Andreeff, M.
(2003). Caspase-independent cell death in AML: caspase inhibition in vitro with pan-caspase inhibitors or in vivo by XIAP or Survivin does not affect cell survival or prognosis. Blood
102: 4179-4186
[Abstract]
[Full Text]
-
Potts, P. R., Singh, S., Knezek, M., Thompson, C. B., Deshmukh, M.
(2003). Critical function of endogenous XIAP in regulating caspase activation during sympathetic neuronal apoptosis. JCB
163: 789-799
[Abstract]
[Full Text]
-
Olson, M. R., Holley, C. L., Gan, E. C., Colon-Ramos, D. A., Kaplan, B., Kornbluth, S.
(2003). A GH3-like Domain in Reaper Is Required for Mitochondrial Localization and Induction of IAP Degradation. J. Biol. Chem.
278: 44758-44768
[Abstract]
[Full Text]
-
Greil, R., Anether, G., Johrer, K., Tinhofer, I.
(2003). Tracking death dealing by Fas and TRAIL in lymphatic neoplastic disorders: pathways, targets, and therapeutic tools. J. Leukoc. Biol.
74: 311-330
[Abstract]
[Full Text]
-
Hu, Y., Cherton-Horvat, G., Dragowska, V., Baird, S., Korneluk, R. G., Durkin, J. P., Mayer, L. D., LaCasse, E. C.
(2003). Antisense Oligonucleotides Targeting XIAP Induce Apoptosis and Enhance Chemotherapeutic Activity against Human Lung Cancer Cells in Vitro and in Vivo. Clin. Cancer Res.
9: 2826-2836
[Abstract]
[Full Text]
-
YANG, Y., YU, X.
(2003). Regulation of apoptosis: the ubiquitous way. FASEB J.
17: 790-799
[Abstract]
[Full Text]
-
Wang, Y., Rippstein, P. U., Tsang, B. K.
(2003). Role and Gonadotrophic Regulation of X-Linked Inhibitor of Apoptosis Protein Expression During Rat Ovarian Follicular Development In Vitro. Biol. Reprod.
68: 610-619
[Abstract]
[Full Text]
-
Muro, I., Hay, B. A., Clem, R. J.
(2002). The Drosophila DIAP1 Protein Is Required to Prevent Accumulation of a Continuously Generated, Processed Form of the Apical Caspase DRONC. J. Biol. Chem.
277: 49644-49650
[Abstract]
[Full Text]
-
Li, S., Zhao, Y., He, X., Kim, T.-H., Kuharsky, D. K., Rabinowich, H., Chen, J., Du, C., Yin, X.-M.
(2002). Relief of Extrinsic Pathway Inhibition by the Bid-dependent Mitochondrial Release of Smac in Fas-mediated Hepatocyte Apoptosis. J. Biol. Chem.
277: 26912-26920
[Abstract]
[Full Text]
-
Putcha, G. V., Harris, C. A., Moulder, K. L., Easton, R. M., Thompson, C. B., Johnson, E. M. Jr.
(2002). Intrinsic and extrinsic pathway signaling during neuronal apoptosis: lessons from the analysis of mutant mice. JCB
157: 441-453
[Abstract]
[Full Text]
-
Robles, M. S., Leonardo, E., Criado, L. M., Izquierdo, M., Martinez-A., C.
(2002). Inhibitor of Apoptosis Protein from Orgyia pseudotsugata Nuclear Polyhedrosis Virus Provides a Costimulatory Signal Required for Optimal Proliferation of Developing Thymocytes. J. Immunol.
168: 1770-1779
[Abstract]
[Full Text]
-
Putcha, G. V., Harris, C. A., Moulder, K. L., Easton, R. M., Thompson, C. B., Johnson, E. M. Jr.
(2002). Intrinsic and extrinsic pathway signaling during neuronal apoptosis: lessons from the analysis of mutant mice. JCB
157: 441-453
[Abstract]
[Full Text]
Top
Abstract
Introduction
