Falastick Gamers | University of Lausanne (original) (raw)

Papers by Falastick Gamers

F1000 - Post-publication peer review of the biomedical literature, 2013

F1000 - Post-publication peer review of the biomedical literature, 2013

Proceedings of the National Academy of Sciences, 2011

The protease activity of the paracaspase Malt1 contributes to antigen receptor-mediated lymphocyt... more The protease activity of the paracaspase Malt1 contributes to antigen receptor-mediated lymphocyte activation and lymphomagenesis. Malt1 activity is required for optimal NF-κB activation, but little is known about the responsible substrate(s). Here we report that Malt1 cleaved the NF-κB family member RelB after Arg-85. RelB cleavage induced its proteasomal degradation and specifically controlled DNA binding of RelA-or c-Rel-containing NF-κB complexes. Overexpression of RelB inhibited expression of canonical NF-κB target genes and led to impaired survival of diffuse large B-cell lymphoma cell lines characterized by constitutive Malt1 activity. These findings identify a central role for Malt1-dependent RelB cleavage in canonical NF-κB activation and thereby provide a rationale for the targeting of Malt1 in immunomodulation and cancer treatment.

Trends in Immunology, 2007

Activation of the transcription factor nuclear factor (NF)-kappaB is essential for the normal fun... more Activation of the transcription factor nuclear factor (NF)-kappaB is essential for the normal functioning of the immune system. Deregulated NF-kappaB signalling in lymphocytes can lead to immunodeficiency, but also to autoimmunity or lymphomas. Many of the signalling components controlling NF-kappaB activation in lymphocytes are now known, but it is less clear how distinct molecular components of this pathway are regulated. Here, we summarize recent findings on post-translational modifications of intracellular components of this pathway. Phosphorylation of the CARMA1 and BCL10 proteins and ubiquitylation of BCL10 affect the formation and stability of the CARMA1-BCL10-MALT1 (CBM) complex, and also control negative feedback regulation of the NF-kappaB signalling pathway. Moreover, the study of BCL10 phosphorylation isoforms has revealed a new mechanism controlling BCL10 nuclear translocation and an unexpected role for BCL10 in the regulation of the actin cytoskeleton.

PLoS ONE, 2013

The mucosa-associated lymphoid tissue protein-1 (MALT1, also known as paracaspase) is a protease ... more The mucosa-associated lymphoid tissue protein-1 (MALT1, also known as paracaspase) is a protease whose activity is essential for the activation of lymphocytes and the growth of cells derived from human diffuse large B-cell lymphomas of the activated B-cell subtype (ABC DLBCL). Crystallographic approaches have shown that MALT1 can form dimers via its protease domain, but why dimerization is relevant for the biological activity of MALT1 remains largely unknown. Using a molecular modeling approach, we predicted Glu 549 (E549) to be localized within the MALT1 dimer interface and thus potentially relevant. Experimental mutation of this residue into alanine (E549A) led to a complete impairment of MALT1 proteolytic activity. This correlated with an impaired capacity of the mutant to form dimers of the protease domain in vitro, and a reduced capacity to promote NF-kB activation and transcription of the growth-promoting cytokine interleukin-2 in antigen receptor-stimulated lymphocytes. Moreover, this mutant could not rescue the growth of ABC DLBCL cell lines upon MALT1 silencing. Interestingly, the MALT1 mutant E549A was unable to undergo monoubiquitination, which we identified previously as a critical step in MALT1 activation. Collectively, these findings suggest a model in which E549 at the dimerization interface is required for the formation of the enzymatically active, monoubiquitinated form of MALT1.

Der Ophthalmologe, 2003

Zusammenfassung Hintergrund. Es gibt derzeit keinen verbindlichen Grenzwert für die Blutalkohol... more Zusammenfassung Hintergrund. Es gibt derzeit keinen verbindlichen Grenzwert für die Blutalkoholkonzentration, ab dem eine Fahruntüchtigkeit im Schiffsverkehr angenommen werden muss und damit eine Bestrafung wegen Trunkenheit nach dem Strafgesetzbuch begründet werden kann. Ziel unseres interdisziplinären Projektes war die Erarbeitung von Datenmaterial, um medizinisch gesicherte Grenzwerte vorzuschlagen. Material und Methode. Der Einfluss von Alkohol auf das visuelle System und die Fähigkeit,

Journal of Leukocyte Biology, 2011

T cell migration, essential for immune surveillance and response, is mediated by the integrin LFA... more T cell migration, essential for immune surveillance and response, is mediated by the integrin LFA-1. CatX, a cysteine carboxypeptidase, is involved in the regulation of T cell migration by interaction with LFA-1. We show that sequential cleavage of C-terminal amino acids from the ␤ 2 cytoplasmic tail of LFA-1, by CatX, enhances binding of the adaptor protein talin to LFA-1 and triggers formation of the latter's high-affinity form. As shown by SPR analysis of peptides constituting the truncated ␤ 2 tail, the cleavage of three C-terminal amino acids by CatX resulted in a 1.6-fold increase of talin binding. Removal of one more amino acid resulted in a 2.5-fold increase over the intact tail. CatX cleavage increased talin-binding affinity to the MD but not the MP talin-binding site on the ␤ 2 tail. This was shown by molecular modeling of the ␤ 2 tail/talin F3 complex to be a result of conformational changes affecting primarily the distal-binding site. Analysis of LFA-1 by conformationspecific mAb showed that CatX modulates LFA-1 affinity, promoting formation of high-affinity from intermediate-affinity LFA-1 but not the initial activation of LFA-1 from a bent to extended form. CatX post-translational modifications may thus represent a mechanism of LFA-1 fine-tuning that enables the trafficking of T cells. J. Leukoc. Biol. 90: 99 -109; 2011.

The Journal of Immunology, 2008

Plasmodium sporozoites traverse several host cells before infecting hepatocytes. In the process, ... more Plasmodium sporozoites traverse several host cells before infecting hepatocytes. In the process, the plasma membranes of the cells are ruptured, resulting in the release of cytosolic factors into the microenvironment. This released endogenous material is highly stimulatory/immunogenic and can serve as a danger signal initiating distinct responses in various cells. Thus, our study aimed at characterizing the effect of cell material leakage during Plasmodium infection on cultured mouse primary hepatocytes and HepG2 cells. We observed that wounded cell-derived cytosolic factors activate NF-B, a main regulator of host inflammatory responses, in cells bordering wounded cells, which are potential host cells for final parasite infection. This activation of NF-B occurred shortly after infection and led to a reduction of infection load in a time-dependent manner in vitro and in vivo, an effect that could be reverted by addition of the specific NF-B inhibitor BAY11-7082. Furthermore, no NF-B activation was observed when Spect ؊/؊ parasites, which are devoid of hepatocyte traversing properties, were used.

Journal of Biological Chemistry, 2001

Fas, a death domain-containing member of the tumor necrosis factor receptor family and its ligand... more Fas, a death domain-containing member of the tumor necrosis factor receptor family and its ligand FasL have been predominantly studied with respect to their capability to induce cell death. However, a few studies indicate a proliferation-inducing signaling activity of these molecules too. We describe here a novel signaling pathway of FasL and the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) that triggers transcriptional activation of the proto-oncogene c-fos, a typical target gene of mitogenic pathways. FasL- and TRAIL-mediated up-regulation of c-Fos was completely dependent on the presence of Fas-associated death domain protein (FADD) and caspase-8, but caspase activity seemed to be dispensable as a pan inhibitor of caspases had no inhibitory effect. Upon overexpression of the long splice form of cellular FADD-like interleukin-1-converting enzyme (FLICE) inhibitory protein (cFLIP) in Jurkat cells, FasL- and TRAIL-induced up-regulation of c-Fos was almost completely blocked. The short splice form of FLIP, however, showed a rather stimulatory effect on c-Fos induction. Together these data demonstrate the existence of a death receptor-induced, FADD- and caspase-8-dependent pathway leading to c-Fos induction that is inhibited by the long splice form FLIP-L.

Cell death & disease, 2011

The cysteine protease caspase-8 is an essential executioner of the death receptor (DR) apoptotic ... more The cysteine protease caspase-8 is an essential executioner of the death receptor (DR) apoptotic pathway. The physiological function of its homologue caspase-10 remains poorly understood, and the ability of caspase-10 to substitute for caspase-8 in the DR apoptotic pathway is still controversial. Here, we analysed the particular contribution of caspase-10 isoforms to DR-mediated apoptosis in neuroblastoma (NB) cells characterised by their resistance to DR signalling. Silencing of caspase-8 in tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-sensitive NB cells resulted in complete resistance to TRAIL, which could be reverted by overexpression of caspase-10A or -10D. Overexpression experiments in various caspase-8-expressing tumour cells also demonstrated that caspase-10A and -10D isoforms strongly increased TRAIL and FasL sensitivity, whereas caspase-10B or -10G had no effect or were weakly anti-apoptotic. Further investigations revealed that the unique C-terminal end...

European Journal of Immunology, 1996

The CD4 or CD8 co-receptors and the T cell receptor (TCR) are though to interact with the same an... more The CD4 or CD8 co-receptors and the T cell receptor (TCR) are though to interact with the same antigen-presenting major histocompatibility complex molecule in a stable ternary complex. Therefore, the TCR and its co-receptor need to come into close proximity on the surface of the T cell. We have previously shown that the interaction of the p56lck SH2 domain with zeta-associated, tyrosine phosphorylated ZAP-70 and Syk kinases leads to an enhanced association of CD4 with TCR/CD3/zeta complex after CD3 stimulation of Jurkat cells. In this report, we analyzed whether a similar mechanism can mediate recruitment of the CD8 alpha alpha and CD8 alpha beta isoforms to the TCR. We demonstrate in vivo in association of CD8 alpha alpha/p56lck with the tyrosine kinase ZAP-70 after CD3 stimulation of Jurkat cells. A phosphopeptide competing in vitro for the binding of tyrosine phosphorylated proteins to the SH2 domain of p56lck specifically impedes the association of ZAP-70 with CD8 alpha alpha/p56lck without affecting the zeta/ZAP-70 interaction. The same peptide is able to compete for the activation-dependent association of the CD8 alpha alpha or CD8 alpha beta isoform with the TCR/CD3/zeta complex. Moreover, co-precipitation of the TCR with both CD8 isoforms was observed after CD3 stimulation. These findings strongly suggest that the p56lck SH2 domain mediates recruitment of CD8/p56lck to the activated TCR/CD3/zeta complex.

Cell Death and Differentiation, 2006

Members of the viral Flice/caspase-8 inhibitory protein (v-FLIP) family prevent induction of apop... more Members of the viral Flice/caspase-8 inhibitory protein (v-FLIP) family prevent induction of apoptosis by death receptors through inhibition of the processing and activation of procaspase-8 and -10 at the level of the receptor-associated death-inducing signaling complex (DISC). Here, we have addressed the molecular function of the v-FLIP member MC159 of the human molluscum contagiosum virus. MC159 FLIP powerfully inhibited both caspase-dependent and caspase-independent cell death induced by Fas. The Cterminal region of MC159 bound TNF receptor-associated factor (TRAF)3, was necessary for optimal TRAF2 binding, and mediated the recruitment of both TRAFs into the Fas DISC. TRAF-binding-deficient mutants of MC159 showed impaired inhibition of FasL-induced caspase-8 processing and Fas internalization, and had reduced antiapoptotic activity. Our findings provide evidence that a MC159/TRAF2/ TRAF3 complex regulates a new aspect of Fas signaling, and identify MC159 FLIP as a molecule that targets multiple features of Fas-induced cell death.

The Journal of Immunology, Oct 15, 1998

FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death... more FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death effector domains and an inactive caspase domain, binds to FADD and caspase-8, and thereby inhibits death receptor-mediated apoptosis. Here, we characterize the inhibitory effect of FLIP on a variety of apoptotic pathways. Human Jurkat T cells undergoing Fas ligandmediated apoptosis in response to CD3 activation were completely resistant when transfected with FLIP. In contrast, the presence of FLIP did not affect apoptosis induced by granzyme B in combination with adenovirus or perforin. Moreover, the Fas ligand, but not the perforin/granzyme B-dependent lytic pathway of CTL, was inhibited by FLIP. Apoptosis mediated by chemotherapeutic drugs (i.e., doxorubicin, etoposide, and vincristine) and gamma irradiation was not affected by FLIP or the absence of Fas, indicating that these treatments can induce cell death in a Fas-independent and FLIP-insensitive manner.

Nature Immunology, 2000

Cell death is achieved by two fundamentally different mechanisms: apoptosis and necrosis. Apoptos... more Cell death is achieved by two fundamentally different mechanisms: apoptosis and necrosis. Apoptosis is dependent on caspase activation, whereas the caspase-independent necrotic signaling pathway remains largely uncharacterized. We show here that Fas kills activated primary T cells efficiently in the absence of active caspases, which results in necrotic morphological changes and late mitochondrial damage but no cytochrome c release.

Curr Biol, 2003

with Bcl10, which, in turn, binds to MALT1, a deathdomain-containing adaptor protein with homolog... more with Bcl10, which, in turn, binds to MALT1, a deathdomain-containing adaptor protein with homology to Biomedical Research Center Chemin des Boveresses 155CH-1066 Epalinges caspases [12, 13]. Overexpression of each of these proteins results in the activation of NF-B [3, 6]. Jurkat Switzerland cells with mutant CARMA1 alleles, with siRNA-induced reduction of CARMA1 expression, and with overexpressed CARD domain mutant CARMA1 displayed re-Summary duced

AfCS-Nature Molecule Pages

Carma1 (CARD-MAGUK1, also called CARD11 or Bimp3) is a caspase-recruitment domain (CARD)-containi... more Carma1 (CARD-MAGUK1, also called CARD11 or Bimp3) is a caspase-recruitment domain (CARD)-containing protein of the membrane-associated guanylate kinase (MAGUK) family of scaffolding proteins, that is predominantly expressed in lymphoid tissues. Carma1 binds via the CARD motif to Bcl10, an adaptor protein central to antigen receptor-induced lymphocyte activation and proliferation. In addition to the CARD motif, Carma1 contains a coiled-coil domain and a MAGUK-typical array of a PDZ, an SH3 and a guanylate kinase (GUK) domain which are critical for the function of the protein. Analyses of Carma1-deficient lymphocyte cell lines or of cells expressing a dominant negative, CARD-mutated form, of Carma1 showed impaired T-cell receptor (TCR)-induced NF-κB and JNK activation. Carma1-deficient mice or mice expressing a CARD-deleted form of Carma1 have an impaired activation of mature B- and T lymphocytes and defects in B-cell development.

Journal of immunology (Baltimore, Md. : 1950), Jan 15, 1998

FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death... more FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death effector domains and an inactive caspase domain, binds to FADD and caspase-8, and thereby inhibits death receptor-mediated apoptosis. Here, we characterize the inhibitory effect of FLIP on a variety of apoptotic pathways. Human Jurkat T cells undergoing Fas ligand-mediated apoptosis in response to CD3 activation were completely resistant when transfected with FLIP. In contrast, the presence of FLIP did not affect apoptosis induced by granzyme B in combination with adenovirus or perforin. Moreover, the Fas ligand, but not the perforin/granzyme B-dependent lytic pathway of CTL, was inhibited by FLIP. Apoptosis mediated by chemotherapeutic drugs (i.e., doxorubicin, etoposide, and vincristine) and gamma irradiation was not affected by FLIP or the absence of Fas, indicating that these treatments can induce cell death in a Fas-independent and FLIP-insensitive manner.

Nature, Jan 10, 1997

The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which ... more The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which can trigger apoptosis. However, Fas surface expression does not necessarily render cells susceptible to Fas ligand-induced death signals, indicating that inhibitors of the apoptosis-signalling pathway must exist. Here we report the characterization of an inhibitor of apoptosis, designated FLIP (for FLICE-inhibitory protein), which is predominantly expressed in muscle and lymphoid tissues. The short form, FLIPs, contains two death effector domains and is structurally related to the viral FLIP inhibitors of apoptosis, whereas the long form, FLIP(L), contains in addition a caspase-like domain in which the active-centre cysteine residue is substituted by a tyrosine residue. FLIPs and FLIP(L) interact with the adaptor protein FADD and the protease FLICE, and potently inhibit apoptosis induced by all known human death receptors. FLIP(L) is expressed during the early stage of T-cell activation,...

F1000 - Post-publication peer review of the biomedical literature, 2013

F1000 - Post-publication peer review of the biomedical literature, 2013

Proceedings of the National Academy of Sciences, 2011

The protease activity of the paracaspase Malt1 contributes to antigen receptor-mediated lymphocyt... more The protease activity of the paracaspase Malt1 contributes to antigen receptor-mediated lymphocyte activation and lymphomagenesis. Malt1 activity is required for optimal NF-κB activation, but little is known about the responsible substrate(s). Here we report that Malt1 cleaved the NF-κB family member RelB after Arg-85. RelB cleavage induced its proteasomal degradation and specifically controlled DNA binding of RelA-or c-Rel-containing NF-κB complexes. Overexpression of RelB inhibited expression of canonical NF-κB target genes and led to impaired survival of diffuse large B-cell lymphoma cell lines characterized by constitutive Malt1 activity. These findings identify a central role for Malt1-dependent RelB cleavage in canonical NF-κB activation and thereby provide a rationale for the targeting of Malt1 in immunomodulation and cancer treatment.

Trends in Immunology, 2007

Activation of the transcription factor nuclear factor (NF)-kappaB is essential for the normal fun... more Activation of the transcription factor nuclear factor (NF)-kappaB is essential for the normal functioning of the immune system. Deregulated NF-kappaB signalling in lymphocytes can lead to immunodeficiency, but also to autoimmunity or lymphomas. Many of the signalling components controlling NF-kappaB activation in lymphocytes are now known, but it is less clear how distinct molecular components of this pathway are regulated. Here, we summarize recent findings on post-translational modifications of intracellular components of this pathway. Phosphorylation of the CARMA1 and BCL10 proteins and ubiquitylation of BCL10 affect the formation and stability of the CARMA1-BCL10-MALT1 (CBM) complex, and also control negative feedback regulation of the NF-kappaB signalling pathway. Moreover, the study of BCL10 phosphorylation isoforms has revealed a new mechanism controlling BCL10 nuclear translocation and an unexpected role for BCL10 in the regulation of the actin cytoskeleton.

PLoS ONE, 2013

The mucosa-associated lymphoid tissue protein-1 (MALT1, also known as paracaspase) is a protease ... more The mucosa-associated lymphoid tissue protein-1 (MALT1, also known as paracaspase) is a protease whose activity is essential for the activation of lymphocytes and the growth of cells derived from human diffuse large B-cell lymphomas of the activated B-cell subtype (ABC DLBCL). Crystallographic approaches have shown that MALT1 can form dimers via its protease domain, but why dimerization is relevant for the biological activity of MALT1 remains largely unknown. Using a molecular modeling approach, we predicted Glu 549 (E549) to be localized within the MALT1 dimer interface and thus potentially relevant. Experimental mutation of this residue into alanine (E549A) led to a complete impairment of MALT1 proteolytic activity. This correlated with an impaired capacity of the mutant to form dimers of the protease domain in vitro, and a reduced capacity to promote NF-kB activation and transcription of the growth-promoting cytokine interleukin-2 in antigen receptor-stimulated lymphocytes. Moreover, this mutant could not rescue the growth of ABC DLBCL cell lines upon MALT1 silencing. Interestingly, the MALT1 mutant E549A was unable to undergo monoubiquitination, which we identified previously as a critical step in MALT1 activation. Collectively, these findings suggest a model in which E549 at the dimerization interface is required for the formation of the enzymatically active, monoubiquitinated form of MALT1.

Der Ophthalmologe, 2003

Zusammenfassung Hintergrund. Es gibt derzeit keinen verbindlichen Grenzwert für die Blutalkohol... more Zusammenfassung Hintergrund. Es gibt derzeit keinen verbindlichen Grenzwert für die Blutalkoholkonzentration, ab dem eine Fahruntüchtigkeit im Schiffsverkehr angenommen werden muss und damit eine Bestrafung wegen Trunkenheit nach dem Strafgesetzbuch begründet werden kann. Ziel unseres interdisziplinären Projektes war die Erarbeitung von Datenmaterial, um medizinisch gesicherte Grenzwerte vorzuschlagen. Material und Methode. Der Einfluss von Alkohol auf das visuelle System und die Fähigkeit,

Journal of Leukocyte Biology, 2011

T cell migration, essential for immune surveillance and response, is mediated by the integrin LFA... more T cell migration, essential for immune surveillance and response, is mediated by the integrin LFA-1. CatX, a cysteine carboxypeptidase, is involved in the regulation of T cell migration by interaction with LFA-1. We show that sequential cleavage of C-terminal amino acids from the ␤ 2 cytoplasmic tail of LFA-1, by CatX, enhances binding of the adaptor protein talin to LFA-1 and triggers formation of the latter's high-affinity form. As shown by SPR analysis of peptides constituting the truncated ␤ 2 tail, the cleavage of three C-terminal amino acids by CatX resulted in a 1.6-fold increase of talin binding. Removal of one more amino acid resulted in a 2.5-fold increase over the intact tail. CatX cleavage increased talin-binding affinity to the MD but not the MP talin-binding site on the ␤ 2 tail. This was shown by molecular modeling of the ␤ 2 tail/talin F3 complex to be a result of conformational changes affecting primarily the distal-binding site. Analysis of LFA-1 by conformationspecific mAb showed that CatX modulates LFA-1 affinity, promoting formation of high-affinity from intermediate-affinity LFA-1 but not the initial activation of LFA-1 from a bent to extended form. CatX post-translational modifications may thus represent a mechanism of LFA-1 fine-tuning that enables the trafficking of T cells. J. Leukoc. Biol. 90: 99 -109; 2011.

The Journal of Immunology, 2008

Plasmodium sporozoites traverse several host cells before infecting hepatocytes. In the process, ... more Plasmodium sporozoites traverse several host cells before infecting hepatocytes. In the process, the plasma membranes of the cells are ruptured, resulting in the release of cytosolic factors into the microenvironment. This released endogenous material is highly stimulatory/immunogenic and can serve as a danger signal initiating distinct responses in various cells. Thus, our study aimed at characterizing the effect of cell material leakage during Plasmodium infection on cultured mouse primary hepatocytes and HepG2 cells. We observed that wounded cell-derived cytosolic factors activate NF-B, a main regulator of host inflammatory responses, in cells bordering wounded cells, which are potential host cells for final parasite infection. This activation of NF-B occurred shortly after infection and led to a reduction of infection load in a time-dependent manner in vitro and in vivo, an effect that could be reverted by addition of the specific NF-B inhibitor BAY11-7082. Furthermore, no NF-B activation was observed when Spect ؊/؊ parasites, which are devoid of hepatocyte traversing properties, were used.

Journal of Biological Chemistry, 2001

Fas, a death domain-containing member of the tumor necrosis factor receptor family and its ligand... more Fas, a death domain-containing member of the tumor necrosis factor receptor family and its ligand FasL have been predominantly studied with respect to their capability to induce cell death. However, a few studies indicate a proliferation-inducing signaling activity of these molecules too. We describe here a novel signaling pathway of FasL and the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) that triggers transcriptional activation of the proto-oncogene c-fos, a typical target gene of mitogenic pathways. FasL- and TRAIL-mediated up-regulation of c-Fos was completely dependent on the presence of Fas-associated death domain protein (FADD) and caspase-8, but caspase activity seemed to be dispensable as a pan inhibitor of caspases had no inhibitory effect. Upon overexpression of the long splice form of cellular FADD-like interleukin-1-converting enzyme (FLICE) inhibitory protein (cFLIP) in Jurkat cells, FasL- and TRAIL-induced up-regulation of c-Fos was almost completely blocked. The short splice form of FLIP, however, showed a rather stimulatory effect on c-Fos induction. Together these data demonstrate the existence of a death receptor-induced, FADD- and caspase-8-dependent pathway leading to c-Fos induction that is inhibited by the long splice form FLIP-L.

Cell death & disease, 2011

The cysteine protease caspase-8 is an essential executioner of the death receptor (DR) apoptotic ... more The cysteine protease caspase-8 is an essential executioner of the death receptor (DR) apoptotic pathway. The physiological function of its homologue caspase-10 remains poorly understood, and the ability of caspase-10 to substitute for caspase-8 in the DR apoptotic pathway is still controversial. Here, we analysed the particular contribution of caspase-10 isoforms to DR-mediated apoptosis in neuroblastoma (NB) cells characterised by their resistance to DR signalling. Silencing of caspase-8 in tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-sensitive NB cells resulted in complete resistance to TRAIL, which could be reverted by overexpression of caspase-10A or -10D. Overexpression experiments in various caspase-8-expressing tumour cells also demonstrated that caspase-10A and -10D isoforms strongly increased TRAIL and FasL sensitivity, whereas caspase-10B or -10G had no effect or were weakly anti-apoptotic. Further investigations revealed that the unique C-terminal end...

European Journal of Immunology, 1996

The CD4 or CD8 co-receptors and the T cell receptor (TCR) are though to interact with the same an... more The CD4 or CD8 co-receptors and the T cell receptor (TCR) are though to interact with the same antigen-presenting major histocompatibility complex molecule in a stable ternary complex. Therefore, the TCR and its co-receptor need to come into close proximity on the surface of the T cell. We have previously shown that the interaction of the p56lck SH2 domain with zeta-associated, tyrosine phosphorylated ZAP-70 and Syk kinases leads to an enhanced association of CD4 with TCR/CD3/zeta complex after CD3 stimulation of Jurkat cells. In this report, we analyzed whether a similar mechanism can mediate recruitment of the CD8 alpha alpha and CD8 alpha beta isoforms to the TCR. We demonstrate in vivo in association of CD8 alpha alpha/p56lck with the tyrosine kinase ZAP-70 after CD3 stimulation of Jurkat cells. A phosphopeptide competing in vitro for the binding of tyrosine phosphorylated proteins to the SH2 domain of p56lck specifically impedes the association of ZAP-70 with CD8 alpha alpha/p56lck without affecting the zeta/ZAP-70 interaction. The same peptide is able to compete for the activation-dependent association of the CD8 alpha alpha or CD8 alpha beta isoform with the TCR/CD3/zeta complex. Moreover, co-precipitation of the TCR with both CD8 isoforms was observed after CD3 stimulation. These findings strongly suggest that the p56lck SH2 domain mediates recruitment of CD8/p56lck to the activated TCR/CD3/zeta complex.

Cell Death and Differentiation, 2006

Members of the viral Flice/caspase-8 inhibitory protein (v-FLIP) family prevent induction of apop... more Members of the viral Flice/caspase-8 inhibitory protein (v-FLIP) family prevent induction of apoptosis by death receptors through inhibition of the processing and activation of procaspase-8 and -10 at the level of the receptor-associated death-inducing signaling complex (DISC). Here, we have addressed the molecular function of the v-FLIP member MC159 of the human molluscum contagiosum virus. MC159 FLIP powerfully inhibited both caspase-dependent and caspase-independent cell death induced by Fas. The Cterminal region of MC159 bound TNF receptor-associated factor (TRAF)3, was necessary for optimal TRAF2 binding, and mediated the recruitment of both TRAFs into the Fas DISC. TRAF-binding-deficient mutants of MC159 showed impaired inhibition of FasL-induced caspase-8 processing and Fas internalization, and had reduced antiapoptotic activity. Our findings provide evidence that a MC159/TRAF2/ TRAF3 complex regulates a new aspect of Fas signaling, and identify MC159 FLIP as a molecule that targets multiple features of Fas-induced cell death.

The Journal of Immunology, Oct 15, 1998

FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death... more FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death effector domains and an inactive caspase domain, binds to FADD and caspase-8, and thereby inhibits death receptor-mediated apoptosis. Here, we characterize the inhibitory effect of FLIP on a variety of apoptotic pathways. Human Jurkat T cells undergoing Fas ligandmediated apoptosis in response to CD3 activation were completely resistant when transfected with FLIP. In contrast, the presence of FLIP did not affect apoptosis induced by granzyme B in combination with adenovirus or perforin. Moreover, the Fas ligand, but not the perforin/granzyme B-dependent lytic pathway of CTL, was inhibited by FLIP. Apoptosis mediated by chemotherapeutic drugs (i.e., doxorubicin, etoposide, and vincristine) and gamma irradiation was not affected by FLIP or the absence of Fas, indicating that these treatments can induce cell death in a Fas-independent and FLIP-insensitive manner.

Nature Immunology, 2000

Cell death is achieved by two fundamentally different mechanisms: apoptosis and necrosis. Apoptos... more Cell death is achieved by two fundamentally different mechanisms: apoptosis and necrosis. Apoptosis is dependent on caspase activation, whereas the caspase-independent necrotic signaling pathway remains largely uncharacterized. We show here that Fas kills activated primary T cells efficiently in the absence of active caspases, which results in necrotic morphological changes and late mitochondrial damage but no cytochrome c release.

Curr Biol, 2003

with Bcl10, which, in turn, binds to MALT1, a deathdomain-containing adaptor protein with homolog... more with Bcl10, which, in turn, binds to MALT1, a deathdomain-containing adaptor protein with homology to Biomedical Research Center Chemin des Boveresses 155CH-1066 Epalinges caspases [12, 13]. Overexpression of each of these proteins results in the activation of NF-B [3, 6]. Jurkat Switzerland cells with mutant CARMA1 alleles, with siRNA-induced reduction of CARMA1 expression, and with overexpressed CARD domain mutant CARMA1 displayed re-Summary duced

AfCS-Nature Molecule Pages

Carma1 (CARD-MAGUK1, also called CARD11 or Bimp3) is a caspase-recruitment domain (CARD)-containi... more Carma1 (CARD-MAGUK1, also called CARD11 or Bimp3) is a caspase-recruitment domain (CARD)-containing protein of the membrane-associated guanylate kinase (MAGUK) family of scaffolding proteins, that is predominantly expressed in lymphoid tissues. Carma1 binds via the CARD motif to Bcl10, an adaptor protein central to antigen receptor-induced lymphocyte activation and proliferation. In addition to the CARD motif, Carma1 contains a coiled-coil domain and a MAGUK-typical array of a PDZ, an SH3 and a guanylate kinase (GUK) domain which are critical for the function of the protein. Analyses of Carma1-deficient lymphocyte cell lines or of cells expressing a dominant negative, CARD-mutated form, of Carma1 showed impaired T-cell receptor (TCR)-induced NF-κB and JNK activation. Carma1-deficient mice or mice expressing a CARD-deleted form of Carma1 have an impaired activation of mature B- and T lymphocytes and defects in B-cell development.

Journal of immunology (Baltimore, Md. : 1950), Jan 15, 1998

FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death... more FLICE-inhibitory protein, FLIP (Casper/I-FLICE/FLAME-1/CASH/CLARP/MRIT), which contains two death effector domains and an inactive caspase domain, binds to FADD and caspase-8, and thereby inhibits death receptor-mediated apoptosis. Here, we characterize the inhibitory effect of FLIP on a variety of apoptotic pathways. Human Jurkat T cells undergoing Fas ligand-mediated apoptosis in response to CD3 activation were completely resistant when transfected with FLIP. In contrast, the presence of FLIP did not affect apoptosis induced by granzyme B in combination with adenovirus or perforin. Moreover, the Fas ligand, but not the perforin/granzyme B-dependent lytic pathway of CTL, was inhibited by FLIP. Apoptosis mediated by chemotherapeutic drugs (i.e., doxorubicin, etoposide, and vincristine) and gamma irradiation was not affected by FLIP or the absence of Fas, indicating that these treatments can induce cell death in a Fas-independent and FLIP-insensitive manner.

Nature, Jan 10, 1997

The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which ... more The widely expressed protein Fas is a member of the tumour necrosis factor receptor family which can trigger apoptosis. However, Fas surface expression does not necessarily render cells susceptible to Fas ligand-induced death signals, indicating that inhibitors of the apoptosis-signalling pathway must exist. Here we report the characterization of an inhibitor of apoptosis, designated FLIP (for FLICE-inhibitory protein), which is predominantly expressed in muscle and lymphoid tissues. The short form, FLIPs, contains two death effector domains and is structurally related to the viral FLIP inhibitors of apoptosis, whereas the long form, FLIP(L), contains in addition a caspase-like domain in which the active-centre cysteine residue is substituted by a tyrosine residue. FLIPs and FLIP(L) interact with the adaptor protein FADD and the protease FLICE, and potently inhibit apoptosis induced by all known human death receptors. FLIP(L) is expressed during the early stage of T-cell activation,...