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Molecular mechanisms of regulation of trafficking and function of different subtypes of NMDA receptors in hippocampal neurons
Skřenková, Kristýna ; Horák, Martin (advisor) ; Balík, Aleš (referee) ; Bendová, Zdeňka (referee)
of Ph.D. thesis Molecular mechanisms of regulation of trafficking and function of different subtypes of NMDA receptors in hippocampal neurons Mgr. Kristýna Skřenková N-methyl-D-aspartate (NMDA) receptors are ionotropic glutamate receptors that play a key role in the mammalian central nervous system. Under physiological conditions, these receptors are important for excitatory synaptic transmission and memory formation. However, under pathological conditions, their abnormal regulation or activation may lead to many neurological and psychiatric disorders, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy or schizophrenia. Previous studies have shown that the number and type of NMDA receptors on the cell surface are regulated at multiple levels, including their synthesis, folding, internalization or degradation. During the trafficking of NMDA receptors to the cell surface membrane, both the agonist binding and receptor activation are examined. Moreover, NMDA receptors undergo many posttranslational modifications such as palmitoylation, phosphorylation or N-glycosylation. In this thesis, we studied the molecular mechanisms that may affect the trafficking and functional properties of NMDA receptors in mammalian cells and rat hippocampal neurons. Specifically, we studied i)...
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Baroque sculpture workshop of Andreas Philipp and Johann Anton Quitteiner
Hořák, Martin ; Adamcová, Kateřina (advisor) ; Oulíková, Petra (referee) ; Zápalková, Helena (referee)
The Quitteiner family sculpture workshop operated in Prague from the turn of the 18th century to the year 1765. The span of its existence is delimited on one side by the arrival of its founder, Andreas Philipp Quitteiner (1679-1729), from Frýdlant in northern Bohemia, and on the other side by the death of the upholder of the family tradition, Johann Anton Quitteiner (1709-1765). During the lifetime of Quitteiner Senior the workshop built its reputation as the leading Prague- based sculpture studio. A. F. Quitteiner strengthened his position while working in the Württemberg region in 1709-1712, and then in 1713 and 1714, when he participated together with other Prague artists in decorating the palace residence at Ludwigsburg. After his return to Prague the elder Quitteiner won recognition alongside the most prominent figures of Czech Baroque sculpture F. M. Brokoff and M. B. Braun, and created his best works, including four statues on the side altars of the Holy Family and Saint John of Nepomuk in Saint Thomas's church in Prague's Lesser Quarter. Quitteiner's son Johann Anton learnt his craft in the family workshop which he took over after his father's death. The starting point for his work was the realistic style of his father. He built on this foundation, however, adding to it elements of...
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Regulation of NMDA receptor trafficking in mammalian cells
Hemelíková, Katarína ; Horák, Martin (advisor) ; Novotný, Jiří (referee) ; Valeš, Karel (referee)
N-methyl-D-aspartate (NMDA) receptors are a subclass of glutamate receptors that play an essential role in mediating excitatory neurotransmission and synaptic plasticity in the mammalian central nervous system (CNS). The activation of NMDA receptors plays a key role in brain development and memory formation. Abnormal regulation of NMDA receptors plays a critical role in the etiology of many neuropsychiatric disorders. NMDA receptors form a heterotetrameric complex composed of GluN1, GluN2(A-D) and GluN3(A, B) subunits. The NMDA receptors surface expression is regulated at multiple levels including early processing (synthesis, subunit assembly, endoplasmic reticulum (ER) processing, intracellular trafficking to the cell surface), internalization, recycling and degradation. NMDA receptors are regulated by the availability of GluN subunits within the ER, the presence of ER retention and export signals, and posttranslational modifications including phosphorylation and palmitoylation. However, the role of N-glycosylation in regulating of NMDA receptor processing has not been studied in detail. The aim of this study was to clarify the mechanisms of regulation of surface expression and functional properties of NMDA receptors. We used a combination of molecular biology, microscopy, biochemistry and...
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Function of the GABA and glycine receptors in the mammalian MNTB
Hrušková, Bohdana ; Tureček, Rostislav (advisor) ; Vyklický, Ladislav (referee) ; Horák, Martin (referee)
GABA and glycine are major inhibitory neurotransmitters in the central nervous system. They act on ionotropic and metabotropic receptors that form oligomeric complexes in plasma membrane of neuronal cells. Pharmacological properties, subcellular distribution and function of GABA and glycine receptors depend on their subunit composition. The thesis was aimed to find subunit composition and physiological role of ionotropic glycine and metabotropic GABAB receptors in neurons of medial nucleus of trapezoid body, MNTB. The nucleus resides in the mammalian auditory brainstem and it is characterized by well defined excitatory and inhibitory inputs. Excitatory fibers form giant glutamatergic nerve terminals, calyces of Held, whereas inhibitory fibers form small GABA/glycinergic boutons. Both types of afferents innervate somatodenritic parts of MNTB principal neurons. The nucleus thus represents a suitable model for studying molecular and cellular mechanisms of interactions between excitation and inhibition. Our experiments were performed using electrophysiology and immunohistochemistry methods. Patch clamp technique was used to record membrane currents and voltages from neurons in live MNTB slices isolated from rats or mice. Spontaneous and sound-evoked activity of murine MNTB neurons was recorded by in...
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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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