Jean Berthelet - Academia.edu (original) (raw)
Papers by Jean Berthelet
médecine/sciences, 2012
The function of IAP has long been limited to an inhibition of apoptosis through their capacity to... more The function of IAP has long been limited to an inhibition of apoptosis through their capacity to bind some caspases. Since the expression of these proteins is altered in some tumor samples, IAPs are targets for anticancer therapy and many small molecules have been designed for their capacity to inhibit IAP-caspase interaction. Unexpectedly, these molecules appeared to significantly affect NF-κB activation. In this review, we will discuss the central role of cIAP1, cIAP2 and XIAP in the regulation of NF-κB activating signaling pathways.
Oncogene, 2013
Tumour necrosis factor-α (TNF) is a cytokine endowed with multiple functions, depending on the ce... more Tumour necrosis factor-α (TNF) is a cytokine endowed with multiple functions, depending on the cellular and environmental context. TNF receptor engagement induces the formation of a multimolecular complex including the TNFR-associated factor TRAF2, the receptor-interaction protein kinase RIP1 and the cellular inhibitor of apoptosis cIAP1, the latter being essential for NF-κB activation. Here, we show that cIAP1 also regulates TNF-induced actin cytoskeleton reorganization through a cdc42-dependent, NF-κB-independent pathway. Deletion of cIAP1 prevents TNF-induced filopodia and cdc42 activation. The expression of cIAP1 or its E3-ubiquitin ligase-defective mutant restores the ability of cIAP1(-/-) MEFs to produce filopodia, whereas a cIAP1 mutant unable to bind TRAF2 does not. Accordingly, the silencing of TRAF2 inhibits TNF-mediated filopodia formation, whereas silencing of RIP1 does not. cIAP1 directly binds cdc42 and promotes its RhoGDIα-mediated stabilization. TNF decreases cIAP1-cdc42 interaction, suggesting that TNF-induced recruitment of cIAP1/TRAF2 to the receptor releases cdc42, which in turn triggers actin remodeling. cIAP1 also regulates cdc42 activation in response to EGF and HRas-V12 expression. A downregulation of cIAP1 altered the cell polarization, the cell adhesion to endothelial cells and cell intercalation, which are cdc42-dependent processes. Finally, we demonstrated that the deletion of cIAP1 regulated the HRas-V12-mediated transformation process, including anchorage-dependent cell growth, tumour growth in a xenograft model and the development of experimental metastasis in the lung.
Cells are constantly exposed to endogenous and exogenous cellular injuries. They cope with stress... more Cells are constantly exposed to endogenous and exogenous cellular injuries. They cope with stressful stimuli by adapting their metabolism and activating various "guardian molecules." These pro-survival factors protect essential cell constituents, prevent cell death, and possibly repair cellular damages. The Inhibitor of Apoptosis (IAPs) proteins display both anti-apoptotic and pro-survival properties and their expression can be induced by a variety of cellular stress such as hypoxia, endoplasmic reticular stress and DNA damage. Thus, IAPs can confer tolerance to cellular stress. This review presents the anti-apoptotic and survival functions of IAPs and their role in the adaptive response to cellular stress. The involvement of IAPs in human physiology and diseases in connection with a breakdown of cellular homeostasis will be discussed.
Inhibitors of Apoptosis (IAPs) are a family of proteins with various biological functions includi... more Inhibitors of Apoptosis (IAPs) are a family of proteins with various biological functions including regulation of innate immunity and inflammation, cell proliferation, cell migration and apoptosis. They are characterized by the presence of at least one N-terminal baculoviral IAP repeat (BIR) domain involved in protein-protein interaction. Most of them also contain a C-terminal RING domain conferring an E3-ubiquitin ligase activity. In drosophila, IAPs are essential to ensure cell survival, preventing the uncontrolled activation of the apoptotic protease caspases. In mammals, IAPs can also regulate apoptosis through controlling caspase activity and caspase-activating platform formation. Mammalian IAPs, mainly X-linked IAP (XIAP) and cellular IAPs (cIAPs) appeared to be important determinants of the response of cells to endogenous or exogenous cellular injuries, able to convert the survival signal into a cell death-inducing signal. This review highlights the role of IAP in regulating apoptosis in Drosophila and Mammals.
médecine/sciences, 2012
> La fonction des IAP (inhibitors of apoptosis proteins) a longtemps été restreinte à une inhibit... more > La fonction des IAP (inhibitors of apoptosis proteins) a longtemps été restreinte à une inhibition de l'apoptose, en raison de leur capacité à lier directement certaines caspases. La mise en évidence d'altérations de l'expression de ces protéines dans des échantillons tumoraux en a fait des cibles privilégiées pour les traitements anticancéreux. De nombreuses molécules ont été développées dans le but d'inhiber la capacité de liaison des IAP avec les caspases. De façon inattendue, ces molécules altèrent considérablement la signalisation NF-B. Dans cette revue, nous discuterons des travaux récents montrant un rôle central de cIAP1, cIAP2 et XIAP dans la régulation des voies de signalisation conduisant à une activation de NF-B. < issus d'organismes invalidés pour ces protéines ont permis de mettre en évidence un rôle important des IAP, principalement cIAP1, cIAP2 et XIAP, dans la signalisation cellulaire conduisant à l'activation des facteurs de transcription NF-B (nuclear factor-kB).
OncoTargets and Therapy, 2013
The inhibitors of apoptosis (IAPs) constitute a family of proteins involved in the regulation of ... more The inhibitors of apoptosis (IAPs) constitute a family of proteins involved in the regulation of various cellular processes, including cell death, immune and inflammatory responses, cell proliferation, cell differentiation, and cell motility. There is accumulating evidence supporting IAP-targeting in tumors: IAPs regulate various cellular processes that contribute to tumor development, such as cell death, cell proliferation, and cell migration; their expression is increased in a number of human tumor samples, and IAP overexpression has been correlated with tumor growth, and poor prognosis or low response to treatment; and IAP expression can be rapidly induced in response to chemotherapy or radiotherapy because of the presence of an internal ribosome entry site (IRES)-dependent mechanism of translation initiation, which could contribute to resistance to antitumor therapy. The development of IAP antagonists is an important challenge and was subject to intense research over the past decade. Six molecules are currently in clinical trials. This review focuses on the role of IAPs in tumors and the development of IAP-targeting molecules for anticancer therapy. Notes: (A) Among IAPs, XIAP is a potent caspase inhibitor. XIAP is composed of three BIR domains, one UBA domain (which binds ubiquitin chains), and one C-terminal RING domain, which confers to XIAP an E3-ubiquitin ligase activity. The first BIR (BIR1) can bind to TAB1, connecting XIAP to the TGFβ signaling pathway. The BIR2 and BIR3 contain a surface hydrophobic groove allowing the interaction with IBM found in caspase-3, -7, and -9 active subunits and in IAP antagonists, such as Smac or HtrA2. Moreover, the linker region upstream of BIR2 binds across the substrate binding pocket of caspase-3 and -7, and BIR3 binds the dimer interface of caspase-9, which hinder substrate accessibility and hide the catalytic residue of caspase. Smac is released from the mitochondria into the cytosol during apoptosis, after a maturation process that removes the N-terminal mitochondrial import signal and exposes the IBM to the N-extremity of the protein. Once cytosolic, Smac forms a symmetric dimer and binds the BIR2 and BIR3 IBM grooves of XIAP, preventing them from binding caspases. In a similar manner, monovalent and bivalent Smac mimetics efficiently bind the BIR2 and BIR3 surface hydrophobic grooves and abrogate XIAP-mediated caspase inhibition. (B−D) Comparison of the XIAP-BIR3 (blue) bound to the IBM of caspase-9 (ATPFQ) (orange) (pdb 1nw9): (B) The IBM (AVPI tetrapeptide) of Smac (red) (pdb 2opz); (C) The monovalent Smac mimetic SM-130 (green) (pdb 2 jk7); and (D) The BIR domains of IAPs are organized in four α-helices and three β-strand sheets maintained by a zinc ion (yellow). IBMs interact with the surface hydrophobic groove of BIRs (constructed using The PyMOL Molecular Graphics System, Version 1.5.0.4 Schrödinger, LLC, New York, NY, USA). Abbreviations: AVPI, Smac N-terminal tetrapeptide; BIR, baculoviral IAP repeat; HtrA2, high temperature requirement protein A2; IAPs, inhibitors of apoptosis; IBM, IAP binding motif; RING, really interesting new gene; SM, Smac mimetic; Smac, second mitochondria-derived activator of caspases; TAB1, TGFβ-activated kinase 1-binding protein 1; TGFβ, transforming growth factor beta; UBA, ubiquitin associated; XIAP, X-chromosome linked IAP; APAF-1, apoptotic peptidase activating factor.
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2013
MOZ and MLL encoding a histone acetyltransferase and a histone methyltransferase, respectively, a... more MOZ and MLL encoding a histone acetyltransferase and a histone methyltransferase, respectively, are targets for recurrent chromosomal translocations found in acute myeloblastic or lymphoblastic leukemia. We have previously shown that MOZ and MLL cooperate to activate HOXA9 gene expression in hematopoietic stem/progenitors cells. To dissect the mechanism of action of this complex, we decided to identify new proteins interacting with MOZ. We found that the scaffold protein Symplekin that supports the assembly of polyadenylation machinery was identified by mass spectrometry. Symplekin interacts and co-localizes with both MOZ and MLL in immature hematopoietic cells. Its inhibition leads to a decrease of the HOXA9 protein level but not of Hoxa9 mRNA and to an over-recruitment of MOZ and MLL onto the HOXA9 promoter. Altogether, our results highlight the role of Symplekin in transcription repression involving a regulatory network between MOZ, MLL and Symplekin.
Symplekin 250 150 100 75 kDa HEK293T B anti-cIAP1 72 kDa KG1 250 kDa anti-MOZ anti-Sympk 170 kDa ... more Symplekin 250 150 100 75 kDa HEK293T B anti-cIAP1 72 kDa KG1 250 kDa anti-MOZ anti-Sympk 170 kDa CD34 + C Supplemental Fig. 1 Supplemental Fig. 1. Symplekin interacts with MOZ. (A) Coomassie blue of proteins coprecipitating with MOZ and the control IP from HEK293T cell lysate, respectively. The immunoprecipitated proteins were resolved by 6% SDS-PAGE and stained with Coomassie blue. Note that several MOZ-binding proteins are resolved. Both lanes were subjected to tandem mass spectrometry. (B) Co-immunoprecipitation of MOZ with cIAP1 in KG1 cells indicates that endogenous MOZ does not interact with endogenous cIAP1. Whole cell soluble extracts were immunoprecipitated with anti-MOZ, then immunoprobed with anti-cIAP1. (C) Co-immunoprecipitation of MOZ with Symplekin (Sympk) in CD34+ cells indicates that endogenous MOZ interacts with endogenous Symplekin. Whole cell soluble extracts were immunoprecipitated with anti-MOZ, then immunoprobed with anti-Sympk.
médecine/sciences, 2012
The function of IAP has long been limited to an inhibition of apoptosis through their capacity to... more The function of IAP has long been limited to an inhibition of apoptosis through their capacity to bind some caspases. Since the expression of these proteins is altered in some tumor samples, IAPs are targets for anticancer therapy and many small molecules have been designed for their capacity to inhibit IAP-caspase interaction. Unexpectedly, these molecules appeared to significantly affect NF-κB activation. In this review, we will discuss the central role of cIAP1, cIAP2 and XIAP in the regulation of NF-κB activating signaling pathways.
Oncogene, 2013
Tumour necrosis factor-α (TNF) is a cytokine endowed with multiple functions, depending on the ce... more Tumour necrosis factor-α (TNF) is a cytokine endowed with multiple functions, depending on the cellular and environmental context. TNF receptor engagement induces the formation of a multimolecular complex including the TNFR-associated factor TRAF2, the receptor-interaction protein kinase RIP1 and the cellular inhibitor of apoptosis cIAP1, the latter being essential for NF-κB activation. Here, we show that cIAP1 also regulates TNF-induced actin cytoskeleton reorganization through a cdc42-dependent, NF-κB-independent pathway. Deletion of cIAP1 prevents TNF-induced filopodia and cdc42 activation. The expression of cIAP1 or its E3-ubiquitin ligase-defective mutant restores the ability of cIAP1(-/-) MEFs to produce filopodia, whereas a cIAP1 mutant unable to bind TRAF2 does not. Accordingly, the silencing of TRAF2 inhibits TNF-mediated filopodia formation, whereas silencing of RIP1 does not. cIAP1 directly binds cdc42 and promotes its RhoGDIα-mediated stabilization. TNF decreases cIAP1-cdc42 interaction, suggesting that TNF-induced recruitment of cIAP1/TRAF2 to the receptor releases cdc42, which in turn triggers actin remodeling. cIAP1 also regulates cdc42 activation in response to EGF and HRas-V12 expression. A downregulation of cIAP1 altered the cell polarization, the cell adhesion to endothelial cells and cell intercalation, which are cdc42-dependent processes. Finally, we demonstrated that the deletion of cIAP1 regulated the HRas-V12-mediated transformation process, including anchorage-dependent cell growth, tumour growth in a xenograft model and the development of experimental metastasis in the lung.
Cells are constantly exposed to endogenous and exogenous cellular injuries. They cope with stress... more Cells are constantly exposed to endogenous and exogenous cellular injuries. They cope with stressful stimuli by adapting their metabolism and activating various "guardian molecules." These pro-survival factors protect essential cell constituents, prevent cell death, and possibly repair cellular damages. The Inhibitor of Apoptosis (IAPs) proteins display both anti-apoptotic and pro-survival properties and their expression can be induced by a variety of cellular stress such as hypoxia, endoplasmic reticular stress and DNA damage. Thus, IAPs can confer tolerance to cellular stress. This review presents the anti-apoptotic and survival functions of IAPs and their role in the adaptive response to cellular stress. The involvement of IAPs in human physiology and diseases in connection with a breakdown of cellular homeostasis will be discussed.
Inhibitors of Apoptosis (IAPs) are a family of proteins with various biological functions includi... more Inhibitors of Apoptosis (IAPs) are a family of proteins with various biological functions including regulation of innate immunity and inflammation, cell proliferation, cell migration and apoptosis. They are characterized by the presence of at least one N-terminal baculoviral IAP repeat (BIR) domain involved in protein-protein interaction. Most of them also contain a C-terminal RING domain conferring an E3-ubiquitin ligase activity. In drosophila, IAPs are essential to ensure cell survival, preventing the uncontrolled activation of the apoptotic protease caspases. In mammals, IAPs can also regulate apoptosis through controlling caspase activity and caspase-activating platform formation. Mammalian IAPs, mainly X-linked IAP (XIAP) and cellular IAPs (cIAPs) appeared to be important determinants of the response of cells to endogenous or exogenous cellular injuries, able to convert the survival signal into a cell death-inducing signal. This review highlights the role of IAP in regulating apoptosis in Drosophila and Mammals.
médecine/sciences, 2012
> La fonction des IAP (inhibitors of apoptosis proteins) a longtemps été restreinte à une inhibit... more > La fonction des IAP (inhibitors of apoptosis proteins) a longtemps été restreinte à une inhibition de l'apoptose, en raison de leur capacité à lier directement certaines caspases. La mise en évidence d'altérations de l'expression de ces protéines dans des échantillons tumoraux en a fait des cibles privilégiées pour les traitements anticancéreux. De nombreuses molécules ont été développées dans le but d'inhiber la capacité de liaison des IAP avec les caspases. De façon inattendue, ces molécules altèrent considérablement la signalisation NF-B. Dans cette revue, nous discuterons des travaux récents montrant un rôle central de cIAP1, cIAP2 et XIAP dans la régulation des voies de signalisation conduisant à une activation de NF-B. < issus d'organismes invalidés pour ces protéines ont permis de mettre en évidence un rôle important des IAP, principalement cIAP1, cIAP2 et XIAP, dans la signalisation cellulaire conduisant à l'activation des facteurs de transcription NF-B (nuclear factor-kB).
OncoTargets and Therapy, 2013
The inhibitors of apoptosis (IAPs) constitute a family of proteins involved in the regulation of ... more The inhibitors of apoptosis (IAPs) constitute a family of proteins involved in the regulation of various cellular processes, including cell death, immune and inflammatory responses, cell proliferation, cell differentiation, and cell motility. There is accumulating evidence supporting IAP-targeting in tumors: IAPs regulate various cellular processes that contribute to tumor development, such as cell death, cell proliferation, and cell migration; their expression is increased in a number of human tumor samples, and IAP overexpression has been correlated with tumor growth, and poor prognosis or low response to treatment; and IAP expression can be rapidly induced in response to chemotherapy or radiotherapy because of the presence of an internal ribosome entry site (IRES)-dependent mechanism of translation initiation, which could contribute to resistance to antitumor therapy. The development of IAP antagonists is an important challenge and was subject to intense research over the past decade. Six molecules are currently in clinical trials. This review focuses on the role of IAPs in tumors and the development of IAP-targeting molecules for anticancer therapy. Notes: (A) Among IAPs, XIAP is a potent caspase inhibitor. XIAP is composed of three BIR domains, one UBA domain (which binds ubiquitin chains), and one C-terminal RING domain, which confers to XIAP an E3-ubiquitin ligase activity. The first BIR (BIR1) can bind to TAB1, connecting XIAP to the TGFβ signaling pathway. The BIR2 and BIR3 contain a surface hydrophobic groove allowing the interaction with IBM found in caspase-3, -7, and -9 active subunits and in IAP antagonists, such as Smac or HtrA2. Moreover, the linker region upstream of BIR2 binds across the substrate binding pocket of caspase-3 and -7, and BIR3 binds the dimer interface of caspase-9, which hinder substrate accessibility and hide the catalytic residue of caspase. Smac is released from the mitochondria into the cytosol during apoptosis, after a maturation process that removes the N-terminal mitochondrial import signal and exposes the IBM to the N-extremity of the protein. Once cytosolic, Smac forms a symmetric dimer and binds the BIR2 and BIR3 IBM grooves of XIAP, preventing them from binding caspases. In a similar manner, monovalent and bivalent Smac mimetics efficiently bind the BIR2 and BIR3 surface hydrophobic grooves and abrogate XIAP-mediated caspase inhibition. (B−D) Comparison of the XIAP-BIR3 (blue) bound to the IBM of caspase-9 (ATPFQ) (orange) (pdb 1nw9): (B) The IBM (AVPI tetrapeptide) of Smac (red) (pdb 2opz); (C) The monovalent Smac mimetic SM-130 (green) (pdb 2 jk7); and (D) The BIR domains of IAPs are organized in four α-helices and three β-strand sheets maintained by a zinc ion (yellow). IBMs interact with the surface hydrophobic groove of BIRs (constructed using The PyMOL Molecular Graphics System, Version 1.5.0.4 Schrödinger, LLC, New York, NY, USA). Abbreviations: AVPI, Smac N-terminal tetrapeptide; BIR, baculoviral IAP repeat; HtrA2, high temperature requirement protein A2; IAPs, inhibitors of apoptosis; IBM, IAP binding motif; RING, really interesting new gene; SM, Smac mimetic; Smac, second mitochondria-derived activator of caspases; TAB1, TGFβ-activated kinase 1-binding protein 1; TGFβ, transforming growth factor beta; UBA, ubiquitin associated; XIAP, X-chromosome linked IAP; APAF-1, apoptotic peptidase activating factor.
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2013
MOZ and MLL encoding a histone acetyltransferase and a histone methyltransferase, respectively, a... more MOZ and MLL encoding a histone acetyltransferase and a histone methyltransferase, respectively, are targets for recurrent chromosomal translocations found in acute myeloblastic or lymphoblastic leukemia. We have previously shown that MOZ and MLL cooperate to activate HOXA9 gene expression in hematopoietic stem/progenitors cells. To dissect the mechanism of action of this complex, we decided to identify new proteins interacting with MOZ. We found that the scaffold protein Symplekin that supports the assembly of polyadenylation machinery was identified by mass spectrometry. Symplekin interacts and co-localizes with both MOZ and MLL in immature hematopoietic cells. Its inhibition leads to a decrease of the HOXA9 protein level but not of Hoxa9 mRNA and to an over-recruitment of MOZ and MLL onto the HOXA9 promoter. Altogether, our results highlight the role of Symplekin in transcription repression involving a regulatory network between MOZ, MLL and Symplekin.
Symplekin 250 150 100 75 kDa HEK293T B anti-cIAP1 72 kDa KG1 250 kDa anti-MOZ anti-Sympk 170 kDa ... more Symplekin 250 150 100 75 kDa HEK293T B anti-cIAP1 72 kDa KG1 250 kDa anti-MOZ anti-Sympk 170 kDa CD34 + C Supplemental Fig. 1 Supplemental Fig. 1. Symplekin interacts with MOZ. (A) Coomassie blue of proteins coprecipitating with MOZ and the control IP from HEK293T cell lysate, respectively. The immunoprecipitated proteins were resolved by 6% SDS-PAGE and stained with Coomassie blue. Note that several MOZ-binding proteins are resolved. Both lanes were subjected to tandem mass spectrometry. (B) Co-immunoprecipitation of MOZ with cIAP1 in KG1 cells indicates that endogenous MOZ does not interact with endogenous cIAP1. Whole cell soluble extracts were immunoprecipitated with anti-MOZ, then immunoprobed with anti-cIAP1. (C) Co-immunoprecipitation of MOZ with Symplekin (Sympk) in CD34+ cells indicates that endogenous MOZ interacts with endogenous Symplekin. Whole cell soluble extracts were immunoprecipitated with anti-MOZ, then immunoprobed with anti-Sympk.