β-Arrestin and its role in signal transduction

β-Arrestin je všudypřítomný protein v buňkách, kde se účastní přenosu informace signálními drahami a může tak ovlivňovat různé buněčné procesy. Konkrétně β-arrestin kooperuje s receptory spřaženými s G proteiny (GPCRs). Po aktivaci receptoru příslušným ligandem dochází k navázání β-arrestinu k receptoru, čímž nastává zeslabení vedení signálu prostřednitvím příslušných G proteinů, neboli desensitizaci, a poté může dojít i k internalizaci receptoru. Kromě toho β-arrestin funguje jako adaptor pro různé molekuly, které se účastní přenosu signálu. Dále může hrát roli i přímo v jádře a ovlivňovat tak transkripci cílových genů. V neposlední řadě je β-arrestin a jeho schopnost regulovat signální dráhy využívána ve výzkumu zaměřeném na vývoj nového typu léčiv, tzv. usměrňovacích ligandů, které po navázání na GPCRs dokáží spouštět pouze jednu určitou aktivitu receptoru a příslušnou buněčnou signalizaci. Powered by TCPDF (www.tcpdf.org)β-Arrestin is a ubiquitous protein in cells, where it is involved in signal transduction and can affect different cellular processes. β-Arrestin cooperates with G protein-coupled receptors (GPCRs). Binding of β-arrestin to a receptor after its activation by a relevant ligand results in attenuation of signal transduction through the cognate G proteins, the process called desensitization, which can be associated with receptor intrenalization. Besides that, β-arrestin acts as adaptor for different molecules, which participate in signal transduction. β-Arrestin also has a role in a regulation of transcription in the cell nucleus. Finally, β-arrestin is explored in research focused on the development of a new type of drugs, so called biased ligands. After binding to a GPCR, these ligands can initiated only one specific activity of the receptor and affect relevant signaling cascades. Powered by TCPDF (www.tcpdf.org)Department of PhysiologyKatedra fyziologiePřírodovědecká fakultaFaculty of Scienc

Procedure for Granting International Protection in the Form of Asylum in the Czech Republic

Procedure for Granting International Protection in the Form of Asylum in the Czech Republic Abstract The content of this work is mainly the course of the asylum procedure from the submission of application for international protection to possible appeals, but also the definition of fundamental concepts, the historical development of the asylum institution, international, EU and national sources related to this procedure. In the introduction of this work I introduced and explained the different concepts without which it would be difficult to understand the asylum issue. In addition to outlining the historical development in this area, I have also taken the liberty of mentioning several major migration waves. Another important part of this thesis are the individual legal sources of this issue. The key documents of international regulation are described. Within the framework of Community law, the thesis lists the essential directives and regulations with a view to the necessary Europeanisation and subsequent incorporation into our legal system. The present work focuses on Europeanisation and the related influence of the CJEU case law on the interpretation of legal norms in the individual Member States of the European Union. It aims primarily to analyze and understand the various stages of the asylum procedure....Řízení o udělení mezinárodní ochrany ve formě azylu v České republice Abstrakt Obsahem této práce je převážně průběh azylového řízení od podání žádosti o udělení mezinárodní ochrany až po případné opravné prostředky, ale také definice zásadních pojmů, historický vývoj institutu azylu, mezinárodní, unijní a vnitrostátní prameny, které se k tomuto řízení vztahují. V úvodu této práce jsem představeny a vysvětleny jednotlivé pojmy, bez kterých by bylo náročné pochopit azylovou problematiku. Kromě nastínění historického vývoje v této oblasti jsem si dovolila i zmínit několik zásadních migračních vln. Další důležitou částí této diplomové práce jsou jednotlivé právní prameny této problematiky. Jsou zde popsány stěžejní dokumenty mezinárodní úpravy. V rámci komunitárního práva jsou v práci vyjmenovány zásadní směrnice a nařízení, a to s ohledem na nezbytnou europeizaci a následnou inkorporaci do našeho právního systému. Předložená práce se zaměřuje na europeizaci a s ní spojený vliv judikatury SDEU na výklad právních norem v jednotlivých členských státech Evropské unie. Klade si za cíl především rozebrat a pochopit jednotlivé fáze azylového řízení. Fáze azylového řízení počínaje podáním žádosti o azyl, následným určením, kdo je a kdo není účastníkem tohoto řízení, výčtem jednotlivých práv a povinností žadatelů o...Department of Administrative Law and Administrative ScienceKatedra správního práva a správní vědyFaculty of LawPrávnická fakult

Quantitative linear dichroism imaging of molecular processes in living cells made simple by open software tools

Fluorescence-detected linear dichroism microscopy allows observing various molecular processes in living cells, as well as obtaining quantitative information on orientation of fluorescent molecules associated with cellular features. Such information can provide insights into protein structure, aid in development of genetically encoded probes, and allow determinations of lipid membrane properties. However, quantitating and interpreting linear dichroism in biological systems has been laborious and unreliable. Here we present a set of open source ImageJ-based software tools that allow fast and easy linear dichroism visualization and quantitation, as well as extraction of quantitative information on molecular orientations, even in living systems. The tools were tested on model synthetic lipid vesicles and applied to a variety of biological systems, including observations of conformational changes during G-protein signaling in living cells, using fluorescent proteins. Our results show that our tools and model systems are applicable to a wide range of molecules and polarization-resolved microscopy techniques, and represent a significant step towards making polarization microscopy a mainstream tool of biological imaging.</p

Adenosine A1-A2A receptor-receptor interaction: contribution to guanosine-mediated effects

Guanosine, a guanine-based purine nucleoside, has been described as a neuromodulator that exerts neuroprotective effects in animal and cellular ischemia models. However, guanosine's exact mechanism of action and molecular targets have not yet been identified. Here, we aimed to elucidate a role of adenosine receptors (ARs) in mediating guanosine effects. We investigated the neuroprotective effects of guanosine in hippocampal slices from A2AR-deficient mice (A2AR-/-) subjected to oxygen/glucose deprivation (OGD). Next, we assessed guanosine binding at ARs taking advantage of a fluorescent-selective A2AR antagonist (MRS7396) which could engage in a bioluminescence resonance energy transfer (BRET) process with NanoLuc-tagged A2AR. Next, we evaluated functional AR activation by determining cAMP and calcium accumulation. Finally, we assessed the impact of A1R and A2AR co-expression in guanosine-mediated impedance responses in living cells. Guanosine prevented the reduction of cellular viability and increased reactive oxygen species generation induced by OGD in hippocampal slices from wild-type, but not from A2AR-/- mice. Notably, while guanosine was not able to modify MRS7396 binding to A2AR-expressing cells, a partial blockade was observed in cells co-expressing A1R and A2AR. The relevance of the A1R and A2AR interaction in guanosine effects was further substantiated by means of functional assays (i.e., cAMP and calcium determinations), since guanosine only blocked A2AR agonist-mediated effects in doubly expressing A1R and A2AR cells. Interestingly, while guanosine did not affect A1R/A2AR heteromer formation, it reduced A2AR agonist-mediated cell impedance responses. Our results indicate that guanosine-induced effects may require both A1R and A2AR co-expression, thus identifying a molecular substrate that may allow fine tuning of guanosine-mediated responses

β-Arrestin and its role in signal transduction

β-Arrestin is a ubiquitous protein in cells, where it is involved in signal transduction and can affect different cellular processes. β-Arrestin cooperates with G protein-coupled receptors (GPCRs). Binding of β-arrestin to a receptor after its activation by a relevant ligand results in attenuation of signal transduction through the cognate G proteins, the process called desensitization, which can be associated with receptor intrenalization. Besides that, β-arrestin acts as adaptor for different molecules, which participate in signal transduction. β-Arrestin also has a role in a regulation of transcription in the cell nucleus. Finally, β-arrestin is explored in research focused on the development of a new type of drugs, so called biased ligands. After binding to a GPCR, these ligands can initiated only one specific activity of the receptor and affect relevant signaling cascades. Powered by TCPDF (www.tcpdf.org

A study of molecular interactions of the μ-opioid receptor: the effect of biased ligands

Receptory spřažené s G proteiny (GPCRs) představují nejpočetnější a fyziologicky velice významnou skupinu membránově vázaných receptorů. Jejich interakce s ostatními molekulami po jejich aktivaci navázáním ligandu zajišťují přenos signálu do buňky. V poslední době se zkoumá zejména ovlivnění funkce receptorů pomocí tzv. usměrňovacích ligandů, které mohou určitým způsobem změnit konformaci receptoru a tím specificky ovlivnit jeho funkci. Tato diplomová práce se soustředila konkrétně na studium vlastností µ-opioidního receptoru (MOR), který je mj. důležitý v nocicepci. Cílem tohoto výzkumu bylo zjistit, jak aktivace MOR vybranými usměrňovacími ligandy (morfin, endomorfin-2 a DAMGO) ovlivňuje fungování a interakce receptoru s potenciálními molekulárními partnery (např. G proteiny a β-arrestinem2). Za použití metody siRNA interference byla snížena exprese vybraných signálních molekul: Gαi1, Gαi2, Gαi3, Gαz a β-arrestin2. Za těchto podmínek byl zkoumán vliv usměrňovacích ligandů na laterální pohyblivost MOR v plazmatické membráně a dále také na aktivitu adenylátcyklázy (AC). Při pozorování laterální mobility MOR jsme detekovali možné zapojení Gαz podjednotky trimerního G proteinu po ovlivnění buněk morfinem a endomorfinem-2. Laterální mobilita MOR byla signifikantně zvýšena, pokud v buňkách byla umlčena...G protein-coupled receptors (GPCRs) are the largest group of membrane-bound receptors. Transmission of signals into the cell interior is mediated through the interactions of these receptors with other signaling molecules. Nowadays, a great attention is devoted to biased ligands which are able to alter the conformation of the receptor in a specific way and thus distinctly affect its function. This diploma thesis was focused on a study of µ-opioid receptor (MOR), which is important in nociception. The aim of this study was to find out, how the activation of MOR by specific biased ligands (morphine, endomorphin-2 and DAMGO) affects the function and the interactions of MOR with potential molecular partners (for example G proteins or β-arrestin) A method of siRNA interference was used to knock down the following selected signaling molecules: Gαi1, Gαi2, Gαi3, Gαz and β-arrestin2. The effect of biased ligands on lateral mobility of MOR in the plasma membrane and on activity of adenylyl cyclase (AC) was examined under these conditions. We observed a possible involvement of Gαz subunit in the lateral mobility of MOR after the effect of morphine and endomorphin-2. The lateral mobility of MOR was significantly increased in cells lacking Gαi2 or Gαi3 or β-arrestin2. In this case the MOR was in inactive state....Katedra fyziologieDepartment of PhysiologyPřírodovědecká fakultaFaculty of Scienc

A study of molecular interactions of the μ-opioid receptor: the effect of biased ligands

G protein-coupled receptors (GPCRs) are the largest group of membrane-bound receptors. Transmission of signals into the cell interior is mediated through the interactions of these receptors with other signaling molecules. Nowadays, a great attention is devoted to biased ligands which are able to alter the conformation of the receptor in a specific way and thus distinctly affect its function. This diploma thesis was focused on a study of µ-opioid receptor (MOR), which is important in nociception. The aim of this study was to find out, how the activation of MOR by specific biased ligands (morphine, endomorphin-2 and DAMGO) affects the function and the interactions of MOR with potential molecular partners (for example G proteins or β-arrestin) A method of siRNA interference was used to knock down the following selected signaling molecules: Gαi1, Gαi2, Gαi3, Gαz and β-arrestin2. The effect of biased ligands on lateral mobility of MOR in the plasma membrane and on activity of adenylyl cyclase (AC) was examined under these conditions. We observed a possible involvement of Gαz subunit in the lateral mobility of MOR after the effect of morphine and endomorphin-2. The lateral mobility of MOR was significantly increased in cells lacking Gαi2 or Gαi3 or β-arrestin2. In this case the MOR was in inactive state...

A study of molecular interactions of the μ-opioid receptor: the effect of biased ligands

G protein-coupled receptors (GPCRs) are the largest group of membrane-bound receptors. Transmission of signals into the cell interior is mediated through the interactions of these receptors with other signaling molecules. Nowadays, a great attention is devoted to biased ligands which are able to alter the conformation of the receptor in a specific way and thus distinctly affect its function. This diploma thesis was focused on a study of µ-opioid receptor (MOR), which is important in nociception. The aim of this study was to find out, how the activation of MOR by specific biased ligands (morphine, endomorphin-2 and DAMGO) affects the function and the interactions of MOR with potential molecular partners (for example G proteins or β-arrestin) A method of siRNA interference was used to knock down the following selected signaling molecules: Gαi1, Gαi2, Gαi3, Gαz and β-arrestin2. The effect of biased ligands on lateral mobility of MOR in the plasma membrane and on activity of adenylyl cyclase (AC) was examined under these conditions. We observed a possible involvement of Gαz subunit in the lateral mobility of MOR after the effect of morphine and endomorphin-2. The lateral mobility of MOR was significantly increased in cells lacking Gαi2 or Gαi3 or β-arrestin2. In this case the MOR was in inactive state...