The Experts below are selected from a list of 233406 Experts worldwide ranked by ideXlab platform
Winfried Weissenhorn - One of the best experts on this subject based on the ideXlab platform.
-
structural studies on the ebola virus Matrix Protein vp40 indicate that Matrix Proteins of enveloped rna viruses are analogues but not homologues
Fems Microbiology Letters, 2004Co-Authors: Joanna Timmins, Rob W.h. Ruigrok, Winfried WeissenhornAbstract:Matrix Proteins are the driving force of assembly of enveloped viruses. Their main function is to interact with and polymerize at cellular membranes and link other viral components to the Matrix–membrane complex resulting in individual particle shapes and ensuring the integrity of the viral particle. Although Matrix Proteins of different virus families show functional analogy, they share no sequence or structural homology. Their diversity is also evident in that they use a variety of late domain motifs to commit the cellular vacuolar Protein sorting machinery to virus budding. Here, we discuss the structural and functional aspects of the filovirus Matrix Protein VP40 and compare them to other known Matrix Protein structures from vesicular stomatitis virus, influenza virus and retroviral Matrix Proteins.
-
Oligomerization and polymerization of the filovirus Matrix Protein VP40
Virology, 2003Co-Authors: Joanna Timmins, Rob W.h. Ruigrok, G. Schoehn, Christine Kohlhaas, Winfried WeissenhornAbstract:The Matrix Protein VP40 from Ebola virus plays an important role in the assembly process of virus particles by interacting with cellular factors, cellular membranes, and the ribonuclearProtein particle complex. Here we show that the N-terminal domain of VP40 folds into a mixture of two different oligomeric states in vitro, namely hexameric and octameric ringlike structures, as detected by gel filtration chromatography, chemical cross-linking, and electron microscopy. Octamer formation depends largely on the interaction with nucleic acids, which in turn confers in vitro SDS resistance. Refolding experiments with a nucleic acid free N-terminal domain preparation reveal a mostly dimeric form of VP40, which is transformed into an SDS resistant octamer upon incubation with E. coli nucleic acids. In addition, we demonstrate that the N-terminal domain of Marburg virus VP40 also folds into ringlike structures, similar to Ebola virus VP40. Interestingly, Marburg virus VP40 rings reveal a high tendency to polymerize into rods composed of stacked rings. These results may suggest distinct roles for different oligomeric forms of VP40 in the filovirus life cycle.
-
ebola virus Matrix Protein vp40 interaction with human cellular factors tsg101 and nedd4
Journal of Molecular Biology, 2003Co-Authors: Joanna Timmins, Rob W.h. Ruigrok, G. Schoehn, S. Scianimanico, T. Vernet, Sylvie Ricardblum, Winfried WeissenhornAbstract:Abstract The Ebola virus Matrix Protein VP40 is a major viral structural Protein and plays a central role in virus assembly and budding at the plasma membrane of infected cells. For efficient budding, a full amino terminus of VP40 is required, which includes a PPXY and a PT/SAP motif, both of which have been proposed to interact with cellular Proteins. Here, we report that Ebola VP40 can interact with cellular factors human Nedd4 and Tsg101 in vitro. We show that WW domain 3 of human Nedd4 is necessary and sufficient for binding to the PPXY motif of VP40, which requires an oligomeric conformation of VP40. Single particle electron microscopy reconstructions indicate that WW3 of Nedd4 is in close contact with the N-terminal domain of hexameric VP40. In contrast, the ubiquitin enzyme variant domain of Tsg101 was sufficient for binding to the PT/SAP motif of VP40, regardless of the oligomeric state of the Matrix Protein. These results suggest that hNedd4 and Tsg101 may play complimentary roles at a late stage of the assembly process, by recruiting cellular factors of two independent pathways to the site of budding at the plasma membrane.
-
Vesicular release of ebola virus Matrix Protein VP40.
Virology, 2001Co-Authors: Joanna Timmins, G. Schoehn, S. Scianimanico, Winfried WeissenhornAbstract:Abstract We have analysed the expression and cellular localisation of the Matrix Protein VP40 from Ebola virus. Full-length VP40 and an N-terminal truncated construct missing the first 31 residues [VP40(31–326)] both locate to the plasma membrane of 293T cells when expressed transiently, while a C-terminal truncation of residues 213 to 326 [VP40(31–212)] shows only expression in the cytoplasm, when analysed by indirect immunofluorescence and plasma membrane preparations. In addition, we find that full-length VP40 [VP40(1–326)] and VP40(31–326) are both released into the cell culture supernatant and float up in sucrose gradients. The efficiency of their release, however, is dependent on the presence of the N-terminal 31 residues. VP40 that is released into the supernatant is resistant to trypsin digestion, a finding that is consistent with the formation of viruslike particles detected by electron microscopy. Together, these results provide strong evidence that Ebola virus VP40 is sufficient for virus assembly and budding from the plasma membrane.
-
Crystal structure of the Matrix Protein VP40 from Ebola virus
The EMBO journal, 2000Co-Authors: Andréa Dessen, Viktor Volchkov, Olga Dolnik, Hans-dieter Klenk, Winfried WeissenhornAbstract:Ebola virus maturation occurs at the plasma membrane of infected cells and involves the clustering of the viral Matrix Protein VP40 at the assembly site as well as its interaction with the lipid bilayer. Here we report the X-ray crystal structure of VP40 from Ebola virus at 2.0 A resolution. The crystal structure reveals that Ebola virus VP40 is topologically distinct from all other known viral Matrix Proteins, consisting of two domains with unique folds, connected by a flexible linker. The C-terminal domain, which is absolutely required for membrane binding, contains large hydrophobic patches that may be involved in the interaction with lipid bilayers. Likewise, a highly basic region is shared between the two domains. The crystal structure reveals how the molecule may be able to switch from a monomeric conformation to a hexameric form, as observed in vitro. Its implications for the assembly process are discussed.
Arnaldo Caruso - One of the best experts on this subject based on the ideXlab platform.
-
role of autophagy in hiv 1 Matrix Protein p17 driven lymphangiogenesis
Journal of Virology, 2017Co-Authors: Pietro Mazzuca, Arnaldo Caruso, Cinzia Giagulli, Stefania Marsico, Marina C Pils, Kai Schulze, Stefania Mitola, Carlos A. Guzmán, Francesca CaccuriAbstract:ABSTRACT AIDS-related lymphomas (ARLs) are expected to increase in the future since combined antiretroviral therapy (cART) enhances the life expectancy of HIV-1-infected (HIV + ) patients but does not affect the occurrence of ARLs to the same extent as that of other tumors. Lymphangiogenesis is essential in supporting growth and metastatic spreading of ARLs. HIV-1 does not infect the neoplastic B cells, but HIV-1 Proteins have been hypothesized to play a key role in sustaining a prolymphangiogenic microenvironment in lymphoid organs. The HIV-1 Matrix Protein p17 is detected in blood and accumulates in the germinal centers of lymph nodes of HIV + patients under successful cART. The viral Protein displays potent lymphangiogenic activity in vitro and in vivo . This is, at least in part, mediated by the secretion of the lymphangiogenic factor endothelin-1, suggesting that activation of a secretory pathway sustains the lymphangiogenic activity of p17. Here, we show that the p17 lymphangiogenic activity occurs on human lymph node-derived lymphatic endothelial cells (LN-LECs) under stress conditions only and relies entirely on activation of an autophagy-based pathway. In fact, induction of autophagy by p17 promotes lymphangiogenesis, whereas pharmacological and genetic inhibition of autophagy inhibits p17-triggered lymphangiogenesis. Similarly, the vasculogenic activity of p17 was totally inhibited in autophagy-incompetent mice. Our findings reveal a previously unrecognized role of autophagy in lymphangiogenesis and open the way to identify novel treatment strategies aimed at inhibiting aberrant tumor-driven lymphangiogenesis in HIV + patients. IMPORTANCE AIDS-related lymphomas (ARLs) are the most common malignancies in HIV-1-infected (HIV + ) patients after the introduction of combined antiretroviral therapy (cART). Lymphangiogenesis is of critical importance in sustaining growth and metastasis of ARLs. Indeed, enhanced lymphangiogenesis occurs in the lymph nodes of HIV + patients under successful cART. The HIV-1 Matrix Protein p17 is detected in blood and accumulates in the lymph node germinal centers even in the absence of virus replication. Several findings suggest a key role for p17 as a microenvironmental factor capable of promoting lymphangiogenesis. Here, we show that p17 promotes lymphangiogenesis of human lymph node-derived lymphatic endothelial cells (LN-LECs). The lymphangiogenic activity of p17 is sustained by an autophagy-based pathway that enables LN-LECs to release prolymphangiogenic factors into the extracellular microenvironment. Our findings indicate that specific targeting of autophagy may provide an important new tool for treating ARLs.
-
hiv 1 Matrix Protein p17 and its receptors
Current Drug Targets, 2015Co-Authors: Francesca Caccuri, Arnaldo Caruso, Stefania Marsico, Simona Fiorentini, Cinzia GiagulliAbstract:The HIV-1 Matrix Protein p17 (p17) plays a crucial role in the virus life cycle. It is released in the extracellular space from HIV-1-infected cells and accumulates in the tissues of patients, even in those successfully treated with highly active antiretroviral therapy. Extracellular p17 deregulates the biological functions of many different cells that are directly or indirectly implicated in AIDS pathogenesis. All p17 actions depend on interaction between its functional epitope (AT20), located at the Protein N-terminal region, and different receptors expressed on target cells. This finding corroborates the importance of impeding p17/p17 receptors interaction as a contribution to block AIDS. In this article we review the interaction of p17 with heparan sulfate proteoglycans (HSPGs) and with the chemokine (C-X-C motif) receptor 1 (CXCR1) and 2 (CXCR2). We provide details on how p17 interacts with its receptors and how these interactions are central to the p17 biological activities. Moreover, we highlight the existence of a p17 variant, named S75X, which displays opposite effects on B-cell proliferation as compared to p17. A two-site model for p17 interaction with G-coupled receptors provides a possible explanation on how mutations naturally occurring within the primary amino acid structure can lead S75X to activate the Akt signaling pathway and to promote B-cell growth and transformation. Identification of p17 interaction with HSPGs, CXCR1 and CXCR2 as a fundamental event in supporting its activity could help to find new treatment approaches aimed at blocking all p17/p17 receptors interactions and, consequently, p17 detrimental activities.
-
hiv 1 Matrix Protein p17 a candidate antigen for therapeutic vaccines against aids
Pharmacology & Therapeutics, 2010Co-Authors: Simona Fiorentini, Francesca Caccuri, Cinzia Giagulli, Anna K Magiera, Arnaldo CarusoAbstract:The success in the development of anti-retroviral therapies (HAART) that contain human immunodeficiency virus type 1 (HIV-1) infection is challenged by the cost of this lifelong therapy and by its toxicity. Immune-based therapeutic strategies that boost the immune response against HIV-1 Proteins or Protein subunits have been recently proposed to control virus replication in order to provide protection from disease development, reduce virus transmission, and help limit the use of anti-retroviral treatments. HIV-1 Matrix Protein p17 is a structural Protein that is critically involved in most stages of the life cycle of the retrovirus. Besides its well established role in the virus life cycle, increasing evidence suggests that p17 may also be active extracellularly in deregulating biological activities of many different immune cells that are directly or indirectly involved in AIDS pathogenesis. Thus, p17 might represent a promising target for developing a therapeutic vaccine as a contribution to combating AIDS. In this article we review the biological characteristics of HIV-1 Matrix Protein p17 and we describe why a synthetic peptide representative of the p17 functional epitope may work as a vaccine molecule capable of inducing anti-p17 neutralizing response against p17 derived from divergent HIV-1 strains.
-
functions of the hiv 1 Matrix Protein p17
New Microbiologica, 2006Co-Authors: Simona Fiorentini, Elena Marini, Sonia Caracciolo, Arnaldo CarusoAbstract:HIV-1 replication is a dynamic process influenced by a combination of viral and host factors. The HIV-1 Matrix Protein p17 is a structural Protein critically involved in most stages of the life cycle of the retrovirus. It participates in the early stages of virus replication as well as in RNA targeting to the plasma membrane, incorporation of the envelope into virions and particle assembly. Besides its well established functions, p17 acts as a viral cytokine that works on preactivated - but not on resting - human T cells promoting proliferation, proinflammatory cytokines release and HIV-1 replication after binding to a cellular receptor (p17R). Thus, p17 might play a key role in the complex network of host- and virus-derived stimulatory factors contributing to create a favourable environment for HIV-1 infection and replication. Here, we present a brief overview of the functions played by the Matrix Protein p17 in the HIV-1 life cycle and summarize the current understanding of how p17 could contribute to the pathogenesis of HIV-1 disease. SUMMARY
Francesca Caccuri - One of the best experts on this subject based on the ideXlab platform.
-
role of autophagy in hiv 1 Matrix Protein p17 driven lymphangiogenesis
Journal of Virology, 2017Co-Authors: Pietro Mazzuca, Arnaldo Caruso, Cinzia Giagulli, Stefania Marsico, Marina C Pils, Kai Schulze, Stefania Mitola, Carlos A. Guzmán, Francesca CaccuriAbstract:ABSTRACT AIDS-related lymphomas (ARLs) are expected to increase in the future since combined antiretroviral therapy (cART) enhances the life expectancy of HIV-1-infected (HIV + ) patients but does not affect the occurrence of ARLs to the same extent as that of other tumors. Lymphangiogenesis is essential in supporting growth and metastatic spreading of ARLs. HIV-1 does not infect the neoplastic B cells, but HIV-1 Proteins have been hypothesized to play a key role in sustaining a prolymphangiogenic microenvironment in lymphoid organs. The HIV-1 Matrix Protein p17 is detected in blood and accumulates in the germinal centers of lymph nodes of HIV + patients under successful cART. The viral Protein displays potent lymphangiogenic activity in vitro and in vivo . This is, at least in part, mediated by the secretion of the lymphangiogenic factor endothelin-1, suggesting that activation of a secretory pathway sustains the lymphangiogenic activity of p17. Here, we show that the p17 lymphangiogenic activity occurs on human lymph node-derived lymphatic endothelial cells (LN-LECs) under stress conditions only and relies entirely on activation of an autophagy-based pathway. In fact, induction of autophagy by p17 promotes lymphangiogenesis, whereas pharmacological and genetic inhibition of autophagy inhibits p17-triggered lymphangiogenesis. Similarly, the vasculogenic activity of p17 was totally inhibited in autophagy-incompetent mice. Our findings reveal a previously unrecognized role of autophagy in lymphangiogenesis and open the way to identify novel treatment strategies aimed at inhibiting aberrant tumor-driven lymphangiogenesis in HIV + patients. IMPORTANCE AIDS-related lymphomas (ARLs) are the most common malignancies in HIV-1-infected (HIV + ) patients after the introduction of combined antiretroviral therapy (cART). Lymphangiogenesis is of critical importance in sustaining growth and metastasis of ARLs. Indeed, enhanced lymphangiogenesis occurs in the lymph nodes of HIV + patients under successful cART. The HIV-1 Matrix Protein p17 is detected in blood and accumulates in the lymph node germinal centers even in the absence of virus replication. Several findings suggest a key role for p17 as a microenvironmental factor capable of promoting lymphangiogenesis. Here, we show that p17 promotes lymphangiogenesis of human lymph node-derived lymphatic endothelial cells (LN-LECs). The lymphangiogenic activity of p17 is sustained by an autophagy-based pathway that enables LN-LECs to release prolymphangiogenic factors into the extracellular microenvironment. Our findings indicate that specific targeting of autophagy may provide an important new tool for treating ARLs.
-
hiv 1 Matrix Protein p17 and its receptors
Current Drug Targets, 2015Co-Authors: Francesca Caccuri, Arnaldo Caruso, Stefania Marsico, Simona Fiorentini, Cinzia GiagulliAbstract:The HIV-1 Matrix Protein p17 (p17) plays a crucial role in the virus life cycle. It is released in the extracellular space from HIV-1-infected cells and accumulates in the tissues of patients, even in those successfully treated with highly active antiretroviral therapy. Extracellular p17 deregulates the biological functions of many different cells that are directly or indirectly implicated in AIDS pathogenesis. All p17 actions depend on interaction between its functional epitope (AT20), located at the Protein N-terminal region, and different receptors expressed on target cells. This finding corroborates the importance of impeding p17/p17 receptors interaction as a contribution to block AIDS. In this article we review the interaction of p17 with heparan sulfate proteoglycans (HSPGs) and with the chemokine (C-X-C motif) receptor 1 (CXCR1) and 2 (CXCR2). We provide details on how p17 interacts with its receptors and how these interactions are central to the p17 biological activities. Moreover, we highlight the existence of a p17 variant, named S75X, which displays opposite effects on B-cell proliferation as compared to p17. A two-site model for p17 interaction with G-coupled receptors provides a possible explanation on how mutations naturally occurring within the primary amino acid structure can lead S75X to activate the Akt signaling pathway and to promote B-cell growth and transformation. Identification of p17 interaction with HSPGs, CXCR1 and CXCR2 as a fundamental event in supporting its activity could help to find new treatment approaches aimed at blocking all p17/p17 receptors interactions and, consequently, p17 detrimental activities.
-
hiv 1 Matrix Protein p17 a candidate antigen for therapeutic vaccines against aids
Pharmacology & Therapeutics, 2010Co-Authors: Simona Fiorentini, Francesca Caccuri, Cinzia Giagulli, Anna K Magiera, Arnaldo CarusoAbstract:The success in the development of anti-retroviral therapies (HAART) that contain human immunodeficiency virus type 1 (HIV-1) infection is challenged by the cost of this lifelong therapy and by its toxicity. Immune-based therapeutic strategies that boost the immune response against HIV-1 Proteins or Protein subunits have been recently proposed to control virus replication in order to provide protection from disease development, reduce virus transmission, and help limit the use of anti-retroviral treatments. HIV-1 Matrix Protein p17 is a structural Protein that is critically involved in most stages of the life cycle of the retrovirus. Besides its well established role in the virus life cycle, increasing evidence suggests that p17 may also be active extracellularly in deregulating biological activities of many different immune cells that are directly or indirectly involved in AIDS pathogenesis. Thus, p17 might represent a promising target for developing a therapeutic vaccine as a contribution to combating AIDS. In this article we review the biological characteristics of HIV-1 Matrix Protein p17 and we describe why a synthetic peptide representative of the p17 functional epitope may work as a vaccine molecule capable of inducing anti-p17 neutralizing response against p17 derived from divergent HIV-1 strains.
Cinzia Giagulli - One of the best experts on this subject based on the ideXlab platform.
-
role of autophagy in hiv 1 Matrix Protein p17 driven lymphangiogenesis
Journal of Virology, 2017Co-Authors: Pietro Mazzuca, Arnaldo Caruso, Cinzia Giagulli, Stefania Marsico, Marina C Pils, Kai Schulze, Stefania Mitola, Carlos A. Guzmán, Francesca CaccuriAbstract:ABSTRACT AIDS-related lymphomas (ARLs) are expected to increase in the future since combined antiretroviral therapy (cART) enhances the life expectancy of HIV-1-infected (HIV + ) patients but does not affect the occurrence of ARLs to the same extent as that of other tumors. Lymphangiogenesis is essential in supporting growth and metastatic spreading of ARLs. HIV-1 does not infect the neoplastic B cells, but HIV-1 Proteins have been hypothesized to play a key role in sustaining a prolymphangiogenic microenvironment in lymphoid organs. The HIV-1 Matrix Protein p17 is detected in blood and accumulates in the germinal centers of lymph nodes of HIV + patients under successful cART. The viral Protein displays potent lymphangiogenic activity in vitro and in vivo . This is, at least in part, mediated by the secretion of the lymphangiogenic factor endothelin-1, suggesting that activation of a secretory pathway sustains the lymphangiogenic activity of p17. Here, we show that the p17 lymphangiogenic activity occurs on human lymph node-derived lymphatic endothelial cells (LN-LECs) under stress conditions only and relies entirely on activation of an autophagy-based pathway. In fact, induction of autophagy by p17 promotes lymphangiogenesis, whereas pharmacological and genetic inhibition of autophagy inhibits p17-triggered lymphangiogenesis. Similarly, the vasculogenic activity of p17 was totally inhibited in autophagy-incompetent mice. Our findings reveal a previously unrecognized role of autophagy in lymphangiogenesis and open the way to identify novel treatment strategies aimed at inhibiting aberrant tumor-driven lymphangiogenesis in HIV + patients. IMPORTANCE AIDS-related lymphomas (ARLs) are the most common malignancies in HIV-1-infected (HIV + ) patients after the introduction of combined antiretroviral therapy (cART). Lymphangiogenesis is of critical importance in sustaining growth and metastasis of ARLs. Indeed, enhanced lymphangiogenesis occurs in the lymph nodes of HIV + patients under successful cART. The HIV-1 Matrix Protein p17 is detected in blood and accumulates in the lymph node germinal centers even in the absence of virus replication. Several findings suggest a key role for p17 as a microenvironmental factor capable of promoting lymphangiogenesis. Here, we show that p17 promotes lymphangiogenesis of human lymph node-derived lymphatic endothelial cells (LN-LECs). The lymphangiogenic activity of p17 is sustained by an autophagy-based pathway that enables LN-LECs to release prolymphangiogenic factors into the extracellular microenvironment. Our findings indicate that specific targeting of autophagy may provide an important new tool for treating ARLs.
-
hiv 1 Matrix Protein p17 and its receptors
Current Drug Targets, 2015Co-Authors: Francesca Caccuri, Arnaldo Caruso, Stefania Marsico, Simona Fiorentini, Cinzia GiagulliAbstract:The HIV-1 Matrix Protein p17 (p17) plays a crucial role in the virus life cycle. It is released in the extracellular space from HIV-1-infected cells and accumulates in the tissues of patients, even in those successfully treated with highly active antiretroviral therapy. Extracellular p17 deregulates the biological functions of many different cells that are directly or indirectly implicated in AIDS pathogenesis. All p17 actions depend on interaction between its functional epitope (AT20), located at the Protein N-terminal region, and different receptors expressed on target cells. This finding corroborates the importance of impeding p17/p17 receptors interaction as a contribution to block AIDS. In this article we review the interaction of p17 with heparan sulfate proteoglycans (HSPGs) and with the chemokine (C-X-C motif) receptor 1 (CXCR1) and 2 (CXCR2). We provide details on how p17 interacts with its receptors and how these interactions are central to the p17 biological activities. Moreover, we highlight the existence of a p17 variant, named S75X, which displays opposite effects on B-cell proliferation as compared to p17. A two-site model for p17 interaction with G-coupled receptors provides a possible explanation on how mutations naturally occurring within the primary amino acid structure can lead S75X to activate the Akt signaling pathway and to promote B-cell growth and transformation. Identification of p17 interaction with HSPGs, CXCR1 and CXCR2 as a fundamental event in supporting its activity could help to find new treatment approaches aimed at blocking all p17/p17 receptors interactions and, consequently, p17 detrimental activities.
-
hiv 1 Matrix Protein p17 a candidate antigen for therapeutic vaccines against aids
Pharmacology & Therapeutics, 2010Co-Authors: Simona Fiorentini, Francesca Caccuri, Cinzia Giagulli, Anna K Magiera, Arnaldo CarusoAbstract:The success in the development of anti-retroviral therapies (HAART) that contain human immunodeficiency virus type 1 (HIV-1) infection is challenged by the cost of this lifelong therapy and by its toxicity. Immune-based therapeutic strategies that boost the immune response against HIV-1 Proteins or Protein subunits have been recently proposed to control virus replication in order to provide protection from disease development, reduce virus transmission, and help limit the use of anti-retroviral treatments. HIV-1 Matrix Protein p17 is a structural Protein that is critically involved in most stages of the life cycle of the retrovirus. Besides its well established role in the virus life cycle, increasing evidence suggests that p17 may also be active extracellularly in deregulating biological activities of many different immune cells that are directly or indirectly involved in AIDS pathogenesis. Thus, p17 might represent a promising target for developing a therapeutic vaccine as a contribution to combating AIDS. In this article we review the biological characteristics of HIV-1 Matrix Protein p17 and we describe why a synthetic peptide representative of the p17 functional epitope may work as a vaccine molecule capable of inducing anti-p17 neutralizing response against p17 derived from divergent HIV-1 strains.
Joanna Timmins - One of the best experts on this subject based on the ideXlab platform.
-
structural studies on the ebola virus Matrix Protein vp40 indicate that Matrix Proteins of enveloped rna viruses are analogues but not homologues
Fems Microbiology Letters, 2004Co-Authors: Joanna Timmins, Rob W.h. Ruigrok, Winfried WeissenhornAbstract:Matrix Proteins are the driving force of assembly of enveloped viruses. Their main function is to interact with and polymerize at cellular membranes and link other viral components to the Matrix–membrane complex resulting in individual particle shapes and ensuring the integrity of the viral particle. Although Matrix Proteins of different virus families show functional analogy, they share no sequence or structural homology. Their diversity is also evident in that they use a variety of late domain motifs to commit the cellular vacuolar Protein sorting machinery to virus budding. Here, we discuss the structural and functional aspects of the filovirus Matrix Protein VP40 and compare them to other known Matrix Protein structures from vesicular stomatitis virus, influenza virus and retroviral Matrix Proteins.
-
Oligomerization and polymerization of the filovirus Matrix Protein VP40
Virology, 2003Co-Authors: Joanna Timmins, Rob W.h. Ruigrok, G. Schoehn, Christine Kohlhaas, Winfried WeissenhornAbstract:The Matrix Protein VP40 from Ebola virus plays an important role in the assembly process of virus particles by interacting with cellular factors, cellular membranes, and the ribonuclearProtein particle complex. Here we show that the N-terminal domain of VP40 folds into a mixture of two different oligomeric states in vitro, namely hexameric and octameric ringlike structures, as detected by gel filtration chromatography, chemical cross-linking, and electron microscopy. Octamer formation depends largely on the interaction with nucleic acids, which in turn confers in vitro SDS resistance. Refolding experiments with a nucleic acid free N-terminal domain preparation reveal a mostly dimeric form of VP40, which is transformed into an SDS resistant octamer upon incubation with E. coli nucleic acids. In addition, we demonstrate that the N-terminal domain of Marburg virus VP40 also folds into ringlike structures, similar to Ebola virus VP40. Interestingly, Marburg virus VP40 rings reveal a high tendency to polymerize into rods composed of stacked rings. These results may suggest distinct roles for different oligomeric forms of VP40 in the filovirus life cycle.
-
ebola virus Matrix Protein vp40 interaction with human cellular factors tsg101 and nedd4
Journal of Molecular Biology, 2003Co-Authors: Joanna Timmins, Rob W.h. Ruigrok, G. Schoehn, S. Scianimanico, T. Vernet, Sylvie Ricardblum, Winfried WeissenhornAbstract:Abstract The Ebola virus Matrix Protein VP40 is a major viral structural Protein and plays a central role in virus assembly and budding at the plasma membrane of infected cells. For efficient budding, a full amino terminus of VP40 is required, which includes a PPXY and a PT/SAP motif, both of which have been proposed to interact with cellular Proteins. Here, we report that Ebola VP40 can interact with cellular factors human Nedd4 and Tsg101 in vitro. We show that WW domain 3 of human Nedd4 is necessary and sufficient for binding to the PPXY motif of VP40, which requires an oligomeric conformation of VP40. Single particle electron microscopy reconstructions indicate that WW3 of Nedd4 is in close contact with the N-terminal domain of hexameric VP40. In contrast, the ubiquitin enzyme variant domain of Tsg101 was sufficient for binding to the PT/SAP motif of VP40, regardless of the oligomeric state of the Matrix Protein. These results suggest that hNedd4 and Tsg101 may play complimentary roles at a late stage of the assembly process, by recruiting cellular factors of two independent pathways to the site of budding at the plasma membrane.
-
Vesicular release of ebola virus Matrix Protein VP40.
Virology, 2001Co-Authors: Joanna Timmins, G. Schoehn, S. Scianimanico, Winfried WeissenhornAbstract:Abstract We have analysed the expression and cellular localisation of the Matrix Protein VP40 from Ebola virus. Full-length VP40 and an N-terminal truncated construct missing the first 31 residues [VP40(31–326)] both locate to the plasma membrane of 293T cells when expressed transiently, while a C-terminal truncation of residues 213 to 326 [VP40(31–212)] shows only expression in the cytoplasm, when analysed by indirect immunofluorescence and plasma membrane preparations. In addition, we find that full-length VP40 [VP40(1–326)] and VP40(31–326) are both released into the cell culture supernatant and float up in sucrose gradients. The efficiency of their release, however, is dependent on the presence of the N-terminal 31 residues. VP40 that is released into the supernatant is resistant to trypsin digestion, a finding that is consistent with the formation of viruslike particles detected by electron microscopy. Together, these results provide strong evidence that Ebola virus VP40 is sufficient for virus assembly and budding from the plasma membrane.