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Glutamate Receptors and Endoplasmic Reticulum Quality Control
Tachezy, Ruth ; Horák, Martin (advisor) ; Adámek, Pavel (referee)
Quality control (QC) is a collection of processes taking part in the biogenesis and architecture of proteins. The objective of this thesis is to describe these processes in detail. QC takes place on many different levels in various compartments of the cell. The focus is on the endoplasmic reticulum (ER) QC interconnected with cytosolic QC. There are multiple steps involved in ERQC: several types of protein translocation to the ER lumen, glycosylation, disulfide bond formation via protein disulfide isomerase, chaperones that assist to achieve a correct conformation, and ER- associated degradation pathway for retranslocation of misfolded proteins back to the cytoplasm, where they are degraded. Cytosolic QC is interconnected with the ERQC through various ways of translocation of proteins to the ER membrane or lumen. Proteins that are retranslocated from ER to the cytosol are ubiquitinated and subsequently degraded in the proteasome. Ubiquitination is a process of targeting a protein for degradation. Cytosolic chaperones and other cellular structures, such as aggresomes, juxtanuclear compartments, and insoluble protein deposits, take part in the ubiquitination. Calcium dysregulation that is linked to QC and correct protein folding in ER is also described. Some of the possible consequences of protein...
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Structural determinants of regulation of surface delivery of NMDA receptors in mammalian cells
Danačíková, Šárka ; Horák, Martin (advisor) ; Bendová, Zdeňka (referee)
N-methyl-D-aspartate (NMDA) receptors are ligand-gated ion channels activated by agonist glutamate and co-agonist glycine. They play a key role in mediating the fast excitatory synaptic neurotransmission in the mammalian central nervous system. To create a functional heterotetrameric receptor, the presence of two GluN1 subunits combined with GluN2 or GluN3 subunits is necessary. Previous studies confirmed the importance of M3 transmembrane helix and extracellularly localized cysteines in regulation of surface expression of functional NMDA receptors. The aim of my thesis is to elucidate an influence of clinically relevant mutations in M3 transmembrane helix and the role of all known cysteines that form disulphide bonds on surface delivery of NMDA receptor expressed in heterologous monkey kidney fibroblasts cell culture (COS-7). Using molecular biology methods, immunocytochemistry and microscopy I found that the clinically relevant mutations M641I and Y647S in GluN1 subunit and also the mutations of particular cysteines forming disulphide bonds caused substantial decrease of surface expression of NMDA receptors. Furthermore, I discovered that the effect of mutated GluN1 subunits on decrease of surface expression depends on the subunit composition. The contribution of my results lies in elucidating the...
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Role of glycosylation of ionotropic glutamate receptors in mammalian neurons
Danačíková, Šárka ; Horák, Martin (advisor) ; Kriška, Ján (referee)
Glutamate is the most abundant excitatory neurotransmitter in the mammalian central nervous system. There are two distinct types of glutamate receptors, ionotropic and metabotropic, present in the mammalian excitatory synapses. My thesis is focused on the ionotropic glutamate receptors, which play critical roles in learning and memory formation. The main subtypes of ionotropic glutamate receptors are α-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA), N-methyl-D-aspartate (NMDA) and kainate receptors. All types of the ionotropic glutamate receptors, which are assembled as tetramers, contain many glycosylation sites, which can be modified by glycans or monosaccharides. The glycans and monosaccharides attached to the ionotropic glutamate receptors have been shown to regulate key processes such as folding of the subunits, transport to the cell surface as well as their functional properties. Recent literature also suggests that many neurological and psychiatric disorders such as schizophrenia exhibit abnormal glycosylation of ionotropic glutamate receptors. Thus, understanding of the molecular mechanisms, which regulate the glycosylation of the ionotropic glutamate receptors, may be important for developing new therapies for the patients with altered functioning of the glutamatergic synapses in the...
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Tax aspects of the immovable property transfers taxation and their property after the recodification of the private law
Horák, Martin ; Boháč, Radim (advisor) ; Novotný, Petr (referee)
The rigorous thesis deals with taxation of against-payment transfers of immovable property and its ownership. In the first part of the thesis the author deals with essential terms related to the topic; the definiton and characteristics of tax, immovable property and forms of immovable property transfers are stated. In the next chapter there are stated tax characteristics including the options of their division accroding to the tax theory, then the Czech tax system is introduced and generally characterised the construction elements of the tax where on their basis there are described further in the thesis particular legal norms. The next part of the thesis deals with legal norms of the taxes themselves which are taxed both against-payment immovable property transfers and immovable property ownership by. First the tax on the acquisition of immovable property is described where the author deals in detail with historical legal norms that precede currently law in force of the tax on the acquisition of immovable property and then analyses the current legal situation. The last part of the chapter provides discussions and suggestions de lege ferenda. The next chapter has the same structure that deals with tax on immovable property. The last chapter provides overview of the taxes that are related to transfer...
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Preach on the Psalm
Horák, Martin ; Filipi, Pavel (advisor) ; Sláma, Petr (referee) ; Chalupa, Petr (referee)
1 Summary This dissertation deals with a question whether and in what circumstances it is possible to preach on the biblical psalms in the church. It elaborates on comprehension of psalms as God's word and therefore an appropriate base for a sermon. Furthermore it illustrates accepted practice of using the psalms for preaching even though liturgical use of psalter was a prayer. The dissertation shows topical, literary and rhetorical inputs the psalms can provide for writing sermons. The final part delivers three examples of sets of sermons employing these options. The work aims to prove the psalms are not only a base for Christian preaching but even a base providing specific possibilities for the preaching. Key words preaching homiletics psalms Old Testament hermeneutics
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Contribution to radiodiagnostics and to treatment of chosen pathological lesions of femur in childhood and in adults
Horák, Martin ; Poučková, Pavla (advisor) ; Marek, Josef (referee) ; Vítek, František (referee)
7 Abstract (AJ) Introduction Radiology examination using specialized modern imaging methods, including CT and MRI, is essential in the diagnosis of congenital and acquired diseases of the musculoskeletal system. The first part of the dissertation deals with certain congenital defects of the short femur, known in the literature as proximal femoral focal deficiency (PFFD). This part summarizes our experience with the radiological findings in the preoperative and postoperative period, with the main attention to the vascular supply to the affected area. The second part of the presentation deals with some aspects of autologous chondrocyte transplantation fixed at two different carriers implanted into post-traumatic articular cartilage defects of the distal femur. Radiological findings are evaluated in the relation to the histopathological findings. Objectives The first part of the study after the distribution of patients with PFFD by current commonly used radiographic classification sets the objective in the extent of scans of the hip joints to specify diagnosis PFFD in each patient and to evaluate in detail changes in the area of disability, especially a course of blood vessels. The evaluation of the radiation burden of repeated X-ray measurements was done with respect to the age of the patients. Tissue samples...
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The mechanism of regulation of NMDA receptors transport to the cell surface
Lichnerová, Katarína ; Horák, Martin (advisor) ; Bendová, Zdeňka (referee)
N-methyl-D-aspartate (NMDA) receptors are a class of ionotropic glutamate receptors, involved in excitatory synaptic transmission, synaptic plasticity and excitotoxicity. They form heterotetrameric complexes composed of GluN1, GluN2A-D and/or GluN3A-B subunits that are activated by glutamate and glycine. Previous reports showed that different subunits of NMDA receptors, especially the GluN2 subunits, confer different functional and pharmacological properties on the receptor complexes. However, the subunit-dependent differences in the regulation of intracellular processing and transport of NMDA receptor subtypes has not been clearly elucidated. The aim of this work was to clarify the mechanisms of regulation of the NMDA receptor transport. In our experiments we performed immunocytochemistry of receptors on heterologous COS-7 cells and cultured cerebellar granule cells (CGC), both expressing recombinant NMDA receptors. The results of my work show that the transport of NMDA receptors is regulated by presence of GluN2A and GluN2B subunits. Our results further showed that transport of the GluN1/GluN2C receptors is regulated by three specific areas of the GluN2C subunit: i) the A2 segment within the amino- terminal domain, ii.) the M3 domain, and iii.) the proximal part of the C-terminus containing the...
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Effect of calcium ions and cholesterol on channel forming activity of Adenylate-cyclase toxin
Doktorová, Eliška ; Fišer, Radovan (advisor) ; Horák, Martin (referee)
1 Abstract Adenylate cyclase toxin (CyaA) is one of the major virulence factors of bacterium Bordetella pertussis, which is a causative agent of whooping cough. CyaA belongs to the family of RTX toxin-hemolysins. The toxin targets primarily cells expressing integrin receptor CD11b/CD18 but it can also penetrate cells lacking this receptor. CyaA acts on host cells by two independent activities. One is formation of small cation-selective channels, which can lead to colloid osmotic lysis of target cells. The second is disruption of cell signaling through the translocation of the adenylate cyclase (AC) domain to host cell cytosol, which leads to the conversion of ATP into cyclic AMP. It was recently shown that cholesterol affects endocytosis of CyaA. CyaA translocates it's AC domain after relocation of CyaA molecule to the cholesterol-rich lipid raft (Bumba et al. 2010). In this work I examined the effect of cholesterol on channel- forming activity and selectivity of ion channels created by CyaA. For measurements I used artificial membranes enriched with cholesterol. CyaA channels are voltage-dependent. The positive membrane potential on the side of toxin is rquired for incorporation of CyaA molecule into cell membrane. I tried to find out whether the value of voltage has effect on channels opening time....
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Defect detection
Horák, Martin ; Boštík, Ondřej (referee) ; Richter, Miloslav (advisor)
Vizuální inspekce desek plošných spoju (DPS) lidmi se stává nemožná z důvodu zvyšující se komplexity a miniaturizace desek plošných spoju. K dosažení vysoké spolehlivosti DPS jsou výrobci nuceni vyvíjet nové metody inspekce, které by zajistily kontinuální kontrolu každé desky a oddělily ty, které nesplňují požadavky na jakost. Jednou z možností je použít automatickou rentgenovou inspekci, kterou se zabývá tato práce.
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Interaction of polyomaviruses with proteasomal system of host cell
Verdánová, Martina ; Drda Morávková, Alena (advisor) ; Horák, Martin (referee)
Interaction of polyomaviruses with proteasomal system of host cells Abstract: Viral family Polyomaviridae includes besides model organisms - mouse polyomavirus and SV40 virus, also human pathogens, for example, BK virus. Polyomaviruses are small non- enveloped viruses with double-stranded DNA. Understanding of their life cycle is important for their use in gene therapy and immunotherapy as well as for prevention and treatment of complications caused by these viruses. This thesis is focused on early phases of MPyV and SV40 infection studying, mainly on delivery of viral genome to nucleus and role of proteasomal system in this stage of infection. It was found out that inhibition of proteasomes by specific inhibitor leads to increase of early non-structural protein LT expression, which was chosen as marker for viral entry to the nucleus and successful viral expression. Relative localization of proteasomes and VP1 protein of MPyV and SV40 was monitored and it showed 10% colocalization of mentioned structures. Further, it was found out that proteasomal inhibitor MG-132 negatively influences the replication of both viral and cellular DNA. Next aim of this diploma thesis was to prepare antigen - unique part of VP2 protein of BKV - for producing antibody. Expression vector with inserted fragment of unique part of...
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