|
|
Role of TCTP1 in plant reproduction
Pitoňak, Oliver ; Hafidh, Said (advisor) ; Lafon Placette, Clément (referee)
TCTP is a conserved eukaryotic protein involved in regulation of multiple cellular processes, such as translation, cell cycle and cell death. Apart from its intracellular functions, TCTP is secreted and participates in human immune response. Dimerization via a terminal cysteine residue is critical for its extracellular function. Multiple sequence alignment of eukaryotic TCTPs revealed that terminal cysteine residue is conserved not only in animals but also in green plant lineage. In contrast to animal model organisms, knowledge about TCTP in plants is limited. Arabidopsis thaliana genome harbors two TCTP paralogs, TCTP1 and TCTP2. TCTP1 expression is highly upregulated in pollen. Previously published studies pointed to its role in embryo development, pollen tube growth and targeting. Using mutant characterization and analysis of subcellular localization, the role of TCTP1 in plant reproduction was investigated in this thesis. Recombinant Arabidopsis thaliana TCTP1 protein was produced along with its potential interacting partners BRL2 and TTL3 in heterologous Escherichia coli system. tctp-1 T- DNA line characterization pointed to TCTP1 role in pollen tube growth. It was expressed in mature pollen and pollen tube under native promoter and localized to the cytoplasm. Recombinant AtTCTP1 formed dimers...
|
|
|
Biophysical characterization of the N-terminal part of protein kinase ASK1.
Honzejková, Karolína ; Obšil, Tomáš (advisor) ; Pavlíček, Jiří (referee)
Apoptosis signal-regulating kinase 1 (ASK1) is an apical kinase of the mitogen-activated protein kinase cascade. Its activity is triggered by various stress stimuli such as reactive oxygen species (ROS), cytokines, endoplasmic reticulum (ER) stress or osmotic stress resulting in the activation of p38 and c-Jun N-terminal kinase metabolic pathways and leading to inflammation or cell death. Dysregulation of ASK1 is linked to several pathologies such as neurodegenerative and cardiovascular diseases and cancer, which makes this protein a potential target of therapeutic intervention. The activity of ASK1 is regulated through protein-protein interactions with 14-3-3 proteins and thioredoxin1 being among the most important negative regulators and tumour necrosis factor receptor-associated factors being an example of positive regulators. Apart from that, ASK1 is also tightly regulated via oligomerization. Despite continual progress being made, the precise molecular mechanism of ASK1 regulation and the role of ASK1 oligomerization in this process still remains unclear to this day owing to the lack of structural data. Interaction of the N-terminal parts of two protomers of ASK1 dimer is one of the key steps in ASK1 activation. It was shown, that the isolated ASK1 catalytic domain (ASK1-CD) forms stable...
|
|
|
The influence of heterodimezation of splicing variants of metobotropic glutamate receptor 1a and 1b on the intracellular distribution of receptor complexes
Dvořáková, Michaela ; Konvalinka, Jan (advisor) ; Vaněk, Ondřej (referee)
L-glutamate is a major excitatory neurotransmitter in vertebrate central nervous system. L-glutamate enables synaptic transmission through ionotropic and metabotropic glutamate receptors. These receptors are indispensable in the brain. The main role of metabotropic glutamate receptors is to mediate slow excitatory and inhibitory responses by activation of intracellular messengers and to regulate cationic channels. Metabotropic glutamate receptors are involved in synaptic plasticity, different types of memory, learning, motoric coordination and neural development. On the other hand excitotoxicity of glutamate is often associated with neurodegenerative processes such as Alzheimer, Huntington and Parkinson disease. Metabotropic glutamate receptors are promising therapeutic targets for a treatment of psychiatric and neurological diseases. Targeted trafficking of metabotropic glutamate receptors to distinct parts of neurons is influenced by neuronal polarity and thus regulates sensing and transmission of extracellular signals. Newly detected heterodimeric receptors might be trafficked in a different way than homodimers and therefore our knowledge of molecular pathways of these complexes could help us with subsequent drug targeting. This work confirms heterodimerization of metabotropic glutamate receptor 1 into...
|
|
|
New components and functions of mitochondrial ATP synthase.
Ho, Dieu Hien ; Pecina, Petr (advisor) ; Kalous, Martin (referee)
The system of oxidative phosphorylation, or respiratory chain in mitochondria gives the eukaryotic cell total majority of the energy it receives and uses in the form of ATP. F1Fo-ATP synthase, powered by the proton-motive force is directly responsible for the ATP synthesis. Diseases connected to the ATP synthesis can have even lethal consequences. There is therefore no doubt about the need for a detailed analysis of the structure of this enzyme. What is left is to reveal the structure of the transmembrane domains, which are not involved in the synthesis itself, but they can for example work as stabilisers or assembly factors. Outside the synthesis activity the dimers of F1Fo-ATP synthase are apparently taking part in the formation of the cristae of the inner membrane of a mitochondrion. Recently, the role of the enzyme is also considered in the creation of the mitochondrial permeability transition pore.
|
|
|
Biophysical characterization of the N-terminal part of protein kinase ASK1.
Honzejková, Karolína ; Obšil, Tomáš (advisor) ; Pavlíček, Jiří (referee)
Apoptosis signal-regulating kinase 1 (ASK1) is an apical kinase of the mitogen-activated protein kinase cascade. Its activity is triggered by various stress stimuli such as reactive oxygen species (ROS), cytokines, endoplasmic reticulum (ER) stress or osmotic stress resulting in the activation of p38 and c-Jun N-terminal kinase metabolic pathways and leading to inflammation or cell death. Dysregulation of ASK1 is linked to several pathologies such as neurodegenerative and cardiovascular diseases and cancer, which makes this protein a potential target of therapeutic intervention. The activity of ASK1 is regulated through protein-protein interactions with 14-3-3 proteins and thioredoxin1 being among the most important negative regulators and tumour necrosis factor receptor-associated factors being an example of positive regulators. Apart from that, ASK1 is also tightly regulated via oligomerization. Despite continual progress being made, the precise molecular mechanism of ASK1 regulation and the role of ASK1 oligomerization in this process still remains unclear to this day owing to the lack of structural data. Interaction of the N-terminal parts of two protomers of ASK1 dimer is one of the key steps in ASK1 activation. It was shown, that the isolated ASK1 catalytic domain (ASK1-CD) forms stable...
|
|
|
New components and functions of mitochondrial ATP synthase.
Ho, Dieu Hien ; Pecina, Petr (advisor) ; Kalous, Martin (referee)
The system of oxidative phosphorylation, or respiratory chain in mitochondria gives the eukaryotic cell total majority of the energy it receives and uses in the form of ATP. F1Fo-ATP synthase, powered by the proton-motive force is directly responsible for the ATP synthesis. Diseases connected to the ATP synthesis can have even lethal consequences. There is therefore no doubt about the need for a detailed analysis of the structure of this enzyme. What is left is to reveal the structure of the transmembrane domains, which are not involved in the synthesis itself, but they can for example work as stabilisers or assembly factors. Outside the synthesis activity the dimers of F1Fo-ATP synthase are apparently taking part in the formation of the cristae of the inner membrane of a mitochondrion. Recently, the role of the enzyme is also considered in the creation of the mitochondrial permeability transition pore.
|
|
|
Role of metabotropic glutamate receptors and their associated proteins in physiology and pathophysiology
Kumpošt, Jiří ; Blahoš, Jaroslav (advisor) ; Dráber, Petr (referee) ; Viklický, Vladimír (referee)
of the thesis Glutamate is a main excitatory neurotransmitter in the brain of mammals, which activates both ionotropic and metabotropic glutamate receptors. Ionotropic receptors are responsible for fast synaptic transmission leading to membrane depolarization and Ca2+ influx into the cell. On the other hand mGlu receptors play an important role in regulation of the transmission via heterotrimeric G-proteins and activation of various signaling pathways. Postsynaptically localized group I mGlu receptors (mGluR1, 5) together with ionotropic NMDA and AMPA receptors share common large receptor signaling complexes, or signalosome facilitating glutamate signal transductions. Individual mGluR1 splice variants are differently associated with signalosome including scaffold proteins like PSD-95 which organize postsynaptic density (PSD). Heterodimerization of different mGluR1 splice variants is a focal point of my thesis together with investigation of recently discovered protein IL1RAPL1 (interleukin-1 receptor accessory protein-like 1) and its role in organization of postsynaptic signalosome. Using biochemical, immunocytochemical and functional assays we showed heterodimers of mGluR1a/1b were expressed on the plasma membrane and that heterodimers are fully functional in the recombinant system. Next we showed...
|
|
|
The influence of heterodimezation of splicing variants of metobotropic glutamate receptor 1a and 1b on the intracellular distribution of receptor complexes
Dvořáková, Michaela ; Konvalinka, Jan (advisor) ; Vaněk, Ondřej (referee)
L-glutamate is a major excitatory neurotransmitter in vertebrate central nervous system. L-glutamate enables synaptic transmission through ionotropic and metabotropic glutamate receptors. These receptors are indispensable in the brain. The main role of metabotropic glutamate receptors is to mediate slow excitatory and inhibitory responses by activation of intracellular messengers and to regulate cationic channels. Metabotropic glutamate receptors are involved in synaptic plasticity, different types of memory, learning, motoric coordination and neural development. On the other hand excitotoxicity of glutamate is often associated with neurodegenerative processes such as Alzheimer, Huntington and Parkinson disease. Metabotropic glutamate receptors are promising therapeutic targets for a treatment of psychiatric and neurological diseases. Targeted trafficking of metabotropic glutamate receptors to distinct parts of neurons is influenced by neuronal polarity and thus regulates sensing and transmission of extracellular signals. Newly detected heterodimeric receptors might be trafficked in a different way than homodimers and therefore our knowledge of molecular pathways of these complexes could help us with subsequent drug targeting. This work confirms heterodimerization of metabotropic glutamate receptor 1 into...
|
guest ::
