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SAP102 Switches the Mechanism of D₁R-Mediated ERK1/2 Activation from a PKA-Independent to PKA-Dependent PathwayMischuk, Bradley 01 December 2020 (has links)
Hyperactivation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) by dopamine D₁ receptor (D₁R) in the striatum is a characteristic feature of several neuropsychiatric conditions, including drug addiction and L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID) within individuals suffering from Parkinson’s disease. However, the current mechanistic gap in understanding of D₁R-mediated regulation of ERK1/2, both in physiology and disease, hampers effective treatment of these conditions. One important factor that is underexplored in this regard is the role played by proteins that physically interact with the intracellular regions of D₁R. Using yeast two-hybrid screens and co-transfected human embryonic kidney 293 (HEK293) cells, our laboratory has recently characterized an interaction between the third intracellular loop of D₁R and synapse-associated protein 102 (SAP102), a member of the membrane-associated guanylate kinase family. Moreover, our lab identified endogenous D₁R-SAP102 complex within rat striatum and hippocampus. Interestingly, SAP102 regulates ERK signaling pathway within the hippocampus, and modulates adenosine A2A receptor-mediated ERK1/2 activation within transfected HEK293 cells. Capitalizing on the above findings, I hypothesized a role for SAP102 in controlling D₁R-mediated ERK1/2 activation. Herein, I demonstrate using co-transfected HEK293 cells that SAP102 alters the temporal activation of ERK1/2 by D₁R. Intriguingly, experiments using the protein kinase A (PKA) inhibitors H89 and protein kinase inhibitor 14-22 amide myristoylated show that SAP102 also facilitates a switch in D₁R-mediated ERK1/2 activation from a PKA-independent to PKA-dependent pathway. Furthermore, SAP102 reduces basal ERK1/2 activation in HEK293 cells, reminiscent of a previously documented role of hippocampal SAP102. To the best of my knowledge, my findings are the first to demonstrate scaffolding protein-mediated switching of a G protein-coupled receptor (GPCR) signaling pathway. Future studies aimed at uncovering the details of this process should provide valuable insight on the mechanisms contributing to D₁R-mediated ERK1/2 activation, and may also offer clues to the existence of similar phenomena for other GPCRs. These studies would also aid development of improved pharmacological treatment options for conditions with dysfunctional D₁R-dependent ERK1/2 activation.
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Load profiling and customer segmentation for demand-side managementBaril, Anne January 2023 (has links)
The energy transition is accompanied by massive electrification of uses and sectors such as transport. As a result, the pressure on the electricity grid is increasing, and the time to connect to the power system is lengthening. Deploying new infrastructure is a laborious and expensive process but there are alternatives to exploit the flexibility of the power grid. The deployment of smart meters opens the door to many applications related to flexibility on the consumer side, to reduce peak loads that threaten grid capacity. Targeting the right consumers for Demand-Side Management (DSM) is a prerequisite to maximizing the chances of success of such programs. This degree project replicates and adapts the method developed in [14] to segment residential customers. It consists of encoding Daily Load Curves (DLC) using a dictionary of Typical Load Profiles (TLP) and grouping consumers according to the distribution of their TLP. A temporal analysis of the main TLP reveals different consumption behaviors. Customers are segmented into groups that reflect the degree of volatility of their consumption. This enables a classification based on the potential for Energy Efficiency (EE) or Demand Response (D/R) programs. We address the issue of attribute detection using the distribution of TLP of customers. In particular, several classification algorithms are compared to detect TLP characteristic of Electric Vehicle (EV). The obtained load shapes show consumption peaks at night, which may correspond to the charging time of EV. The method is discussed, especially the choice of the number of load profiles to be included in the dictionary of TLP. It proves to be useful to group consumers with similar consumption profiles and opens the door to applications such as individual household consumption forecasting. / Energiomställningen kräver en massiv elektrifiering av användningsområden och sektorer som t.ex. transportsektorn. Detta leder till att trycket på elnätet ökar och att tiden för att ansluta sig till elnätet blir allt längre. Att bygga ut ny infrastruktur är en mödosam och dyr process, men det finns alternativ för att utnyttja elnätets flexibilitet. Utplaceringen av smarta mätare öppnar dörren för många tillämpningar som rör flexibilitet på konsumentsidan, för att minska toppbelastningar som hotar nätkapaciteten. Att rikta in sig på rätt konsumenter för DSM är en förutsättning för att maximera chanserna att lyckas med sådana program. I detta examensarbete replikeras och anpassas den metod som utvecklats i [14] för att segmentera hushållskunder. Den består av att koda DLC med hjälp av ett lexikon av TLP och gruppera konsumenter enligt fördelningen av deras TLP. En tidsmässig analys av de viktigaste TLP avslöjar olika konsumtionsbeteenden. Kunderna delas in i grupper som återspeglar graden av volatilitet i deras konsumtion. Detta möjliggör en klassificering baserad på potentialen för EE eller D/R-program. Vi tar upp frågan om attributdetektering med hjälp av fördelningen av TLP hos kunderna. I synnerhet jämförs flera klassificeringsalgoritmer för att upptäcka TLP som är karakteristiska för EV. De erhållna belastningsformerna visar konsumtionstoppar på natten, vilket kan motsvara laddningstiden för EV. Metoden diskuteras, särskilt valet av antalet belastningsprofiler som ska ingå i ordlistan för TLP. Metoden visar sig vara användbar för att gruppera konsumenter med liknande förbrukningsprofiler och öppnar dörren för tillämpningar som prognostisering av enskilda hushålls förbrukning.
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Urban Growth and Environmental Risks - A GIS-Based Analysis of Landslide Susceptibility in Bukavu (Democratic Republic of the Congo)Paul, Simon January 2019 (has links)
The city of Bukavu, located at the eastern border of the Democratic Republic of Congo in the province of South Kivu, is a large and densely populated urban agglomeration that has experienced rapid growth during recent years. At the same time, Bukavu has been repeatedly struck by environmental hazards, especially by devastating landslides. The steepness of slopes in the city’s hilly and mountainous terrain is one of the most important factors contributing to landslide susceptibility, but the anthropogenic impact resulting from uncoordinated urban sprawl and land cover change additionally plays a crucial role in exacerbating the vulnerability of neighbourhoods. This thesis utilizes GIS software to provide cartographic material for landslide risk assessment in Bukavu and the city’s surroundings. It examines risk exposure related to slope inclination of densely built-up areas, the spatial development of the city and urban growth tendencies, and complements these aspects with information about land cover and the terrain.
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Biochemical and biophysical studies on adenosine receptors and their interaction partnersNanekar, R. (Rahul) 16 February 2016 (has links)
Abstract
Adenosine receptors are heterotrimeric guanine nucleotide-binding (G protein)-coupled receptors (GPCRs) that mediate the effects of the endogenous agonist adenosine. The adenosine A3 receptor (A3R) is the least explored among the four human adenosine receptor subtype members (A1, A2A, A2B and A3) and it is implicated in both neuroprotective and neurodegenerative effects.
During the course of this work, the production of the recombinant human A3R in yeast and insect cells was evaluated and heteromerization between the human adenosine A2A receptor (A2AR) and the dopamine D2 receptor (D2R) was studied. A3R with carboxyl-terminal GFP tag was expressed in the yeast Saccharomyces cerevisiae upto 15 mg per litre of culture. Another yeast Pichia pastoris increased the expression up to 108 mg/L of the same receptor when grown in bioreactors. Despite the very high expression levels, purification of A3R from both yeasts was a daunting task, as the aggregation of the receptor could not be averted. In this study, insect cells have been found out to be more suitable host for A3R expression: 10µg of the monomeric A3R could be purified from one liter of insect cell culture.
For successful crystallization thermostability of the A3R was to be improved. This work has demonstrated that insertion of T4L, a fusion protein, in the third intracellular loop of A3R increased the thermostability of the receptor by 10°C. As a next step, the combination of point mutations based on alanine-scanning mutagenesis and a fusion protein approach could be useful to stabilize and further crystallize the A3R. This work has demonstrated that the amounts of A3R expressed in insect cells and the final yield of the receptor isolated by affinity purifications, forms a good basis for the beginning of biochemical characterization
Receptor heteromerization is a mechanism used by GPCRs to diversify their signaling properties and functions. The human A2AR and D2R heteromers exist in the GABAergic enkephalinergic neurons. The domains responsible for forming intermolecular contacts were purified from Escherichia coli (E. coli). Using biochemical/biophysical techniques such as native-PAGE and mass spectrometry, It was validated that purified carboxyl-terminus of the A2AR and the 3rd intracellular loop of D2R form heterodimers. The investigation of purified calmodulin protein binding to the 3rd intracellular loop of D2R showed that the protein-protein interactions are calcium dependent. / Tiivistelmä
Adenosiinireseptorit kuuluvat G-proteiinikytkeiset reseptorit (GPCR:t) proteiiniperheeseen. Adenosiinireseptorit välittävät endogeenisen ligandinsa adenosiinin vaikutuksia solukalvolta solunsisäisiin signaalijärjestelmiin. Adenosiini A3 reseptori (A3R) on adenosiinireseptorien neljästä alatyypistä (A1, A2A, A2B ja A3) vähiten tutkittu. Aikaisempien tutkimusten perusteella A3 reseptori yhdistetään sekä hermosoluja suojaaviin että rappeuttaviin tapahtumiin.
Tässä työssä arvioitiin sekä ihmisen rekombinantti-A3R:n tuottumista hiiva- ja hyönteissoluissa että tutkittiin ihmisen adenosiini A2A reseptorin (A2AR) ja dopamiini D2 reseptorin (D2R) heteromerisoitumista. Rekombinantti A3 reseptori- vihreä fluoresoiva proteiini (GFP) fuusioproteiinia tuotettiin Saccharomyces cerevisiae -hiivassa 15 mg litrassa kasvatusliuosta. Pichia pastoris -hiivakanta taas kasvatti saman reseptorin tuottumista aina 108 mg/l saakka, kun tuotto tehtiin bioreaktorissa. Hyvin korkeasta tuottotasosta huolimattaA3R:n puhdistus hiivasta oli ylitsepääsemätön tehtävä, sillä reseptorin saostumista ei voinut välttää. Työssä havaittiin, että hyönteissolut sopivat paremmin A3R:n tuottoon: noin 10 µg monomeerista A3R:a voitiin puhdistaa litran hyönteissoluviljelmästä.
Reseptorin stabiilisuuden lisääminen helpottaa reseptorin biokemiallista ja biofysikaalista karakterisointia. Tässä työssä osoitettiin, että T4L-proteiinin lisääminen A3R:n kolmannen solunsisäisen silmukan paikalle lisää reseptorin lämpöstabiilisuutta 10 °C. Jatkotutkimuksissa voitaisiin käyttää alaniiniskannausmutageneesiin perustuvien pistemutaatioiden ja fuusioproteiinin yhdistelmää A3R:n lisästabilointiin ja kiteytykseen. Tämän työn perusteella määrät, joilla A3R tuottuu hyönteissoluissa ja jotka saadaan eristettyä affiniteettipuhdistuksilla, muodostavat hyvän perustan proteiinin biokemialliselle karakterisoinnille.
Reseptorin heteromerisoituminen on GPCR:en käyttämä mekanismi signalointiominaisuuksien ja toimintojen monipuolistamiseksi. Ihmisessä A2AR ja D2R heteromeereja on GABAergisissä enkefalinergisissä hermosoluissa. Molekyylien välisiin kontakteihin osallistuvat domeenit puhdistettiin Escherichia coli (E. coli) -bakteerista. Biokemiallisia ja biofysikaalisia tekniikoita kuten natiivi-PAGE:a ja massaspektrometriaa käyttäen vahvistettiin, että puhdistettu A2AR:n karboksiterminaalinen osa ja D2R:n kolmas solunsisäinen silmukka muodostavat heterodimeereja. Myös tutkittaessa puhdistetun kalmoduliini-proteiinin sitoutumista D2R:n kolmanteen solunsisäiseen silmukkaan osoitettiin proteiini-proteiini -vuorovaikutuksen olevan kalsiumista riippuvainen.
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Analýza organizační kultury v dopravní společnosti / Analysis of the organizational culture of transport companyKučerová, Eliška January 2016 (has links)
The aim of the thesis is to analyse the organizational culture in three local companies of the transport corporation. The analysis is carried out with the aim to map the organizational culture in the local companies. At the beginning of the work is described theory, which is composed from the organizational culture, models of individual organizational cultures and elements that may affect the strength of the organizational culture and others. In the empirical part are analysed the data obtained by various methods of diagnostics organizational culture. These include observation, interviewing and analysis the documents of company. At the end of this thesis are found the recommendations for the company.
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