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The effect of 14-3-3 protein on intradomain interaction of ubiquitin ligase Nedd4-2
Pohl, Pavel ; Obšilová, Veronika (advisor) ; Žáková, Lenka (referee) ; Pavlíček, Jiří (referee)
EN The human ubiquitin ligase Nedd4-2 (NEDD4L) ubiquitinates a wide range of membrane proteins and receptors, playing a key role in maintaining homeostasis. This enzyme is regulated by phosphorylation and subsequent interaction with 14-3-3 proteins, which primarily affects its ability to interact with various substrates. However, very little is known about the molecular basis of this protein-protein interaction. In this work, we focused on biophysical characterization of the role of individual phosphorylation sites and also on mapping the structural changes in the Nedd4- 2 protein induced by 14-3-3 protein binding. Our experiments using analytical ultracentrifugation methods revealed that two phosphorylation sites Ser342 and Ser448 are primarily required for stable binding of Nedd4-2 to 14-3-3 proteins. The crystal structure of the 14-3-3ηΔC:Nedd4-2335-455 T367A complex than revealed the simultaneous binding of both phosphorylated residues to the binding groove of 14-3-3 protein. Subsequent modeling based on small-angle X-ray scattering and chemical cross-linking data combined with mass spectrometry indicated extensive structural changes in the individual domains of the Nedd4-2 protein. Binding of 14-3-3η protein blocks the WW3 domain of Nedd4-2 in the central channel of 14-3-3 protein, while...
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Structural biology of complex of rat NK cell receptors NKR-P1B and Clrb
Dvorská, Anna ; Vaněk, Ondřej (advisor) ; Ingr, Marek (referee)
The Natural Killer (NK) cells have an important role in the nonspecific immunity of the or- ganism. They have the ability to identify and to kill tumor cells and cells infected by a virus without preceding sensitization by antigen. Their function is directed by the amount of sti- mulation and inhibition receptors interacting with ligands on the tumor or infected cell. This thesis focuses on the preparation and the study of the complex of rat NK cellular inhi- bition receptor NKR-P1B ("natural killer cell receptor - protein 1B") and its ligand Clrb ("C-type lectin-related ligand b"). The Clrb initiates the inhibition of NKR-P1B, meaning that if the cell express Clrb, it won't be destroyed. If the cell gets infected by the rat cytome- galovirus, it loses Clrb from its surface and its destruction is therefore no longer prevented. Cells infected with this virus defend themselves from destruction by expression of the viral gene of C-type lectin RCTL, which is a homolog of Clrb. Transient transfection of human embryonic kidney 293 cell line with simple glycosylation (HEK293S GnTI− ) was used for the recombinant preparation of the soluble form of these two receptors of the rat NK cells. The native forms of the receptors - disulfidic homo- dimers - were prepared as the fusion construct with IgG Fc (using...
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Structure and function of C-type lectin NK cell receptors studied by recombinant expression and protein crystallography
Vaněk, Ondřej ; Bezouška, Karel (advisor) ; Hrabal, Richard (referee) ; Bařinka, Cyril (referee)
Department of Biochemistry, Faculty of Science, Charles University in Prague 2010 Structure and function of C-type lectin NK cell receptors studied by recombinant expression and protein crystallography Abstract of Ph.D. thesis Ondřej Vaněk Supervisor: Prof. RNDr. Karel Bezouška, DSc. Natural killer cells (NK cells) were found out for their ability to spontaneously kill certain allogeneic tumour cell lines, without any previous sensitization. NK cells are part of non- adaptive immune response with very short reaction time against pathogens such as viruses, intracellular bacteria, parasites, and they are responsible for elimination of certain tumour cells and thus they are able to fight against malignancy and formation of metastasis. Activity of NK cells is regulated by the balance between activation and inhibitory signals mediated by the NK cell surface receptors. From the structural point of view, the majority of NK cell surface receptors could be classified as the C-type lectin or immunoglobulin-like receptors. One of many C-type lectin subgroups are type II lymphocyte receptors that are expressed on the NK cell surface. This study had two main aims. The first one was to find suitable expression and purification systems for selected C-type lectin receptors of NK cells and the other one was to perform their...
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Study of some markers of human leukemia
Pospíšilová, Klára ; Jílek, Petr (advisor) ; Skálová, Lenka (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Study Field: zbioanalytical chemistry Candidate: Klára Pospíšilová Thesis Supervisor: PharmDr. P. Jílek, PharmDr. Consultant: RNDr. P. Řezáčová, MD., Ph.D., Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic Thesis Title: Study of some markers of human leukemia Abstract: Immunophenotyping of leukemia cells is an important part of leukemia diagnosis. Immunophenotype is determined by flow cytometry using monoclonal antibodies against antigens expressed by these cells. Antigen CD44 is one of many CD markers used in immunophenotyping of leukemias. Protein crystallography of a complex between CD44 antigen and its ligand, hyaluronate, bring more detailed information about the structure of the binding site, which may help develop strategies for influencing the binding and thus for potential therapeutic intervention.
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Structural studies of LEDGF/p75 interactions
Těšina, Petr
3 ABSTRACT LEDGF/p75 protein is a human transcriptional co-activator and epigenetic reader associated with transcriptionally active chromatin. It is crucial for HIV integration and MLL1 fusion-driven leukemia development. Interactions of LEDGF/p75 with HIV integrase (HIV IN) and MLL1-menin complex are considered an attractive therapeutic target for drug development. LEDGF/p75 interacts with both HIV IN and MLL1-menin complex through its integrase binding domain (IBD). While the pathophysiological interactions of LEDGF/p75 IBD were intensively studied, little was known about the physiological ones. In addition to HIV IN and MLL1, the LEDGF/p75 IBD also interacts with JPO2, PogZ, ASK and MLL2. In search for specific inhibitors of LEDGF/p75 IBD interaction with HIV IN and MLL1, it is essential to obtain detailed information about its interactions with all binding partners. The IBD-MLL1-menin complex has been structurally characterized, but only partially. Using NMR spectroscopy, we identified and mapped a novel part of the IBD-MLL1 interface. This additional interface is able to maintain the interaction between LEDGF/p75 and MLL1 even without the presence of menin, which was considered necessary. Moreover, colony forming assays of primary leukemic blasts revealed that this additional interface is essential for...
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Identification of small compounds disrupting protein-protein interaction in influenza A polymerase.
Hejdánek, Jakub ; Konvalinka, Jan (advisor) ; Obšil, Tomáš (referee)
Influenza virus causes severe respiratory infections in birds and mammals and it is responsible for up to half a million deaths of human beings worldwide each year. Two molecular targets in influenza viral life cycle, neuraminidase and M2 proton channel are exploited in treatment. However, the recent emergence of new pandemic type along with increasing resistance against approved drugs has urged the need for a new drug target discovery and potential search of its inhibitor. Recently, an interesting protein-protein interaction between two subunits PA and PB1 of influenza A viral polymerase has been identified by X-ray crystallography as a new promising drug target. The fact that relatively few residues drive the binding and that the binding interface is highly conserved presents an intriguing possibility to identify antiviral lead compounds effective against all subtypes of influenza A virus. In our laboratory, we expressed and purified two fusion tag constructs of the recombinant C-terminal domain of polymerase acidic subunit (CPA) from the pandemic isolate A/California/07/2009 H1N1. First, GST-CPA fusion protein was used for kinetic evaluation of PA-PB1 interaction by surface plasmon resonance. Moreover, this construct was used in the development of high-throughput screening method for search of...
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Structure and function of C-type lectin NK cell receptors studied by recombinant expression and protein crystallography
Vaněk, Ondřej
Department of Biochemistry, Faculty of Science, Charles University in Prague 2010 Structure and function of C-type lectin NK cell receptors studied by recombinant expression and protein crystallography Abstract of Ph.D. thesis Ondřej Vaněk Supervisor: Prof. RNDr. Karel Bezouška, DSc. Natural killer cells (NK cells) were found out for their ability to spontaneously kill certain allogeneic tumour cell lines, without any previous sensitization. NK cells are part of non- adaptive immune response with very short reaction time against pathogens such as viruses, intracellular bacteria, parasites, and they are responsible for elimination of certain tumour cells and thus they are able to fight against malignancy and formation of metastasis. Activity of NK cells is regulated by the balance between activation and inhibitory signals mediated by the NK cell surface receptors. From the structural point of view, the majority of NK cell surface receptors could be classified as the C-type lectin or immunoglobulin-like receptors. One of many C-type lectin subgroups are type II lymphocyte receptors that are expressed on the NK cell surface. This study had two main aims. The first one was to find suitable expression and purification systems for selected C-type lectin receptors of NK cells and the other one was to perform their...
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Identification of small compounds disrupting protein-protein interaction in influenza A polymerase.
Hejdánek, Jakub ; Konvalinka, Jan (advisor) ; Obšil, Tomáš (referee)
Influenza virus causes severe respiratory infections in birds and mammals and it is responsible for up to half a million deaths of human beings worldwide each year. Two molecular targets in influenza viral life cycle, neuraminidase and M2 proton channel are exploited in treatment. However, the recent emergence of new pandemic type along with increasing resistance against approved drugs has urged the need for a new drug target discovery and potential search of its inhibitor. Recently, an interesting protein-protein interaction between two subunits PA and PB1 of influenza A viral polymerase has been identified by X-ray crystallography as a new promising drug target. The fact that relatively few residues drive the binding and that the binding interface is highly conserved presents an intriguing possibility to identify antiviral lead compounds effective against all subtypes of influenza A virus. In our laboratory, we expressed and purified two fusion tag constructs of the recombinant C-terminal domain of polymerase acidic subunit (CPA) from the pandemic isolate A/California/07/2009 H1N1. First, GST-CPA fusion protein was used for kinetic evaluation of PA-PB1 interaction by surface plasmon resonance. Moreover, this construct was used in the development of high-throughput screening method for search of...
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Structural studies of LEDGF/p75 interactions
Těšina, Petr
3 ABSTRACT LEDGF/p75 protein is a human transcriptional co-activator and epigenetic reader associated with transcriptionally active chromatin. It is crucial for HIV integration and MLL1 fusion-driven leukemia development. Interactions of LEDGF/p75 with HIV integrase (HIV IN) and MLL1-menin complex are considered an attractive therapeutic target for drug development. LEDGF/p75 interacts with both HIV IN and MLL1-menin complex through its integrase binding domain (IBD). While the pathophysiological interactions of LEDGF/p75 IBD were intensively studied, little was known about the physiological ones. In addition to HIV IN and MLL1, the LEDGF/p75 IBD also interacts with JPO2, PogZ, ASK and MLL2. In search for specific inhibitors of LEDGF/p75 IBD interaction with HIV IN and MLL1, it is essential to obtain detailed information about its interactions with all binding partners. The IBD-MLL1-menin complex has been structurally characterized, but only partially. Using NMR spectroscopy, we identified and mapped a novel part of the IBD-MLL1 interface. This additional interface is able to maintain the interaction between LEDGF/p75 and MLL1 even without the presence of menin, which was considered necessary. Moreover, colony forming assays of primary leukemic blasts revealed that this additional interface is essential for...
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