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The Role of Tyrosine Kinase Activity of Mitochondrial ERBB2/HER2 in Breast Cancer
Novotná, Eliška ; Rohlena, Jakub (advisor) ; Vrbacký, Marek (referee)
Breast cancer is a common malignant disease affecting millions of women worldwide. Amplification of HER2 oncogene, a tyrosine kinase receptor, in breast cancer allows application of targeted therapy, but approximately one third of patients develop resistance to treatment. Relocalization of HER2 from the plasma membrane into the mitochondria was found and suggested as one of the potential causes of such resistance. Here we document that the function of mitochondrial HER2 is distinct from that of HER2 in the plasma membrane. Mitochondrial HER2 enhances cancer cell energetic metabolism, proliferation and migration in vitro, and tumour formation in vivo in mice correlating with elevated level of ROS signalling. The kinase activity of mitochondrial HER2 is unaffected, therefore I investigated its role in mitochondrial HER2 function. Moderate, endogenous levels of the kinase activity of mitochondrial HER2 drive pro-tumorigenic properties of breast cancer cells, while constitutive kinase activity sensitizes these cells to cell death and attenuates tumour formation in animal models. On the other hand, impairment of kinase activity due to mutation in the ATP binding site of mitochondrial HER2 supports adherence-independent growth in vitro and tumor growth in vivo. We propose that HER2 function in...
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Functional characterisation of new components of mitochondrial proteome.
Kovalčíková, Jana ; Vrbacký, Marek (advisor) ; Červinková, Zuzana (referee) ; Ješina, Pavel (referee)
1 Abstract It has been estimated that the mammalian mitochondrial proteome consists of ~1500 distinct proteins and approximately one quarter of them is still not fully characterized. One of these proteins is TMEM70, protein involved in the biogenesis of the eukaryotic F1Fo-ATP synthase. TMEM70 mutations cause isolated deficiency of ATP synthase often resulting in a fatal neonatal mitochondrial encephalocardiomyopathies in patients. To understand the molecular mechanism of TMEM70 action, we generated constitutive Tmem70 knockout mice, which led to embryonic lethal phenotype with disturbed ATP synthase biogenesis. Subsequently generated inducible Tmem70 mouse knockout was lethal by the week 8 post induction. It exhibited primarily impaired liver function, which contrasts with the predominantly cardiologic phenotype at disease onset in humans. Liver mitochondria revealed formation of labile ATP synthase subcomplexes lacking subunit c. Thus, in case of TMEM70 deficiency c-oligomer was not incorporated into ATP synthase, which led to critical impairment of mitochondrial energy provision, analogous to TMEM70 dysfunction in humans. In TMEM70 deficient models, the ATP synthase deficiency reached the 'threshold' for its pathologic presentation, which we quantified at 30 %. We observed compensatory increases in the...
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Recombinant expression of chloride channel from E. coliand its structure characterization
Hausner, Jiří ; Man, Petr (advisor) ; Vrbacký, Marek (referee)
Chloride channel family has been shown to play a significant role in physiological homeostasis processes. The function mechanism of these proteins has not yet been clearly understood. Their deficiency or mutation causes serious human illnesses. Our understanding of the chloride channels' transporting mechanisms can lead to better treatment of these illnesses. As mammalian chloride channels are difficult to prepare in laboratory, the experiments are usually done on homologous chloride channels from prokaryotic organisms. The structures of prokaryotic chloride channels have been solved and moreover they are produced with high yields. Most experiments currently use protein crystallography and provide a static picture of the system. This thesis is focused on the study of structural changes of an E. coli chloride channel using hydrogen/deuterium exchange. This method enables us to monitor dynamic conformation changes dependent on pH and exchanged ions. The measurements were done for the protonated (pH 4.5) and deprotonated state (pH 7.5) and/or in the presence of various anions: Cl− , SCN− , I− , F− , TAR. (tartaric anion). The obtained results justified the theories explaining the function of chloride channel as Cl− /H+ antiporter and provided new findings. Subject words biochemistry, protein...
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Proteomic study of human tooth dentin
Zettlová, Ludmila ; Jágr, Michal (advisor) ; Vrbacký, Marek (referee)
Proteome analysis of dentin in human teeth adult subjects was conducted to optimize the two dimensional gel electrophoresis (2-DE) analysis of proteins from the dental tissue. The third molar teeth were cleaned, crushed and extracted in guanidine and EDTA buffer. Extracted proteins were separated by 2-DE, digested with trypsin to peptides and subsequently analyzed using nLC MS/MS. Totally, 7 unique proteins were identified in the samples. The use of IPG strips with different range of the pH gradient and the subsequent comparison of 2 DE gels unfortunately did not bring important new information, because common keratin, collagen and serum albumin proteins were identified.
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Expression of the recombinant extracellular parts of human leukocyte receptors LLT1 and NKR-P1A
Vostárek, František ; Novák, Petr (advisor) ; Vrbacký, Marek (referee)
NK cells are characterized as large granular lymphocytes that play important role in innate immunity. They are called as "first line defense", because of their capability to kill the target cells very fast, in a few minutes. They recognize the target cells using their surface receptors. This diploma thesis describes the preparation of extracellular domains of the human leukocyte receptor hNKR-P1A and its physiological ligand LLT1. The proteins were produced in E. coli as inclusion bodies, refolded in vitro by rapid dilution method (hNKR-P1A) and slow dilution method (LLT1). The proteins were purificated by chromatography and characterized by mass spectrometry techniques.
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The role of NADPH oxidase and ros in invadopodia formation
Hanušová, Kristýna ; Vrbacký, Marek (referee) ; Brábek, Jan (advisor)
Invadopodia as specific organelles enabling tumour cells movement, spreading over the organism and ultimately formation of metastasis are possible and promising targets of tumour therapy. Recently, many interesting facts about assembly and mechanism of function of invadopodia were discovered. Invadopodia are centres of ECM degradation by extra-cellular proteases facilitating an invasion of tumour cells. For creation of invadopodia a precisely localized increased production of ROS is necessary. ROS work as crucial signalling molecules and participate in many processes resulting in invadopodia formation. ROS in tumour cells are produced by specific extra-mitochondrial NADPH oxidases (Nox). Several regulatory molecules participating in activation and localization of Nox to invadopodia have been discovered recently (Tks organizer proteins). Furthermore, a regulatory role of Src kinase in ROS production and subsequent invadopodia formation was confirmed. Key words: ECM degradation, invadopodia, invasion, proteases, Nox, ROS, Src kinase, Tks proteins
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