Résumé : L’expression de surface des récepteurs couplés aux protéines G (GPCRs) est un processus hautement régulé et très important dans le maintien de l’homéostasie cellulaire. En effet, un déséquilibre dans leur niveau d’expression est souvent relié à différentes pathologies comme le cancer, le diabète, l’obésité, les maladies cardiovasculaires et les maladies neurodégénératives. C’est pourquoi la compréhension des mécanismes moléculaires influençant ce phénomène est si importante et nous permettra d’élaborer et/ou d’améliorer les médicaments ciblant la régulation de ce processus. Il est bien connu qu’un des acteurs importants dans le trafic vésiculaire des GPCRs est représenté par la famille des Rab GTPases. Effectivement plusieurs de ces dernières, soit les Rabs 1, 2, 4, 5, 6, 7, 8 et 11 pour ne nommer que les plus connues, modulent l’expression de surface des GPCRs. De plus, certaines études soulèvent la possibilité qu’un GPCR soit lui-même capable de réguler son propre trafic intracellulaire, et ce grâce à son interaction avec les Rab GTPases. Toutefois, le mécanisme emprunté par le GPCR pour atteindre cette fin reste à élucider. Dans le présent travail, je démontre que le GPCR, β2AR, module non seulement la maturation de la petite protéine G Rab11a grâce à son interaction avec la Rab GéranylGéranylTransférase (RGGT), mais influence également son activation en modulant son ubiquitination via son association avec la E3-ubiquitine ligase, HACE1. De plus, je révèle que la sous-unité alpha de la RGGT (RGGTA) accroît significativement la maturation et le transport antérograde du récepteur β2AR, ce qui souligne ainsi un nouveau rôle cellulaire pour cette protéine. L’ensemble des résultats générés appuie l’hypothèse qu’un GPCR puisse contrôler son propre routage intracellulaire, et éclaircit les mécanismes utilisés pour réguler l’activé de la Rab GTPase avec laquelle il interagit. // Abstract : Cell surface expression of G Protein-Coupled Receptors (GPCRs) is a highly regulated and very important phenomenon for keeping cellular homeostasis. In fact, dysregulation of their cell expression is related to many diseases like cancer, neurological disorders, obesity, diabetes and cardiovascular diseases. These facts illustrate how important understanding the molecular mechanisms involved in cell surface transport of those receptors is, which will help us in designing or improving drugs which actually target this pathway. Rab GTPases are proteins known for being essential regulators of GPCR vesicular trafficking. Indeed, an increasing number of studies report the implication of Rab1, 2, 4, 5, 6, 7, 8 and 11 (to cite the most frequently studied) cell surface transport of GPCRs. Moreover, some studies also put forward the possibility that a GPCR might be able to regulate its own cellular trafficking by interacting and controlling activation of Rab GTPases. However, the mechanism involved in this process remains to be clarified. In the present study, I demonstrate that the prototypic GPCR, β2AR, not only modulates prenylation/maturation of the small G protein Rab11a by interacting with Rab GeranylGeranylTransferase (RGGT), but also influences Rab11a activation by modulating its ubiquitination via its association with the E3-ubiquitin ligase, HACE1. Furthermore, I reveal that the α subunit of the RGGT (RGGTA) also promotes the maturation and anterograde transport of the receptor, which highlight a new cellular role for this protein. Altogether, those results support the hypothesis that GPCRs control their own trafficking, and shed light on some of the mechanisms that might be employed by those receptors in activation of Rab GTPases.

Target of Rapamycin Complex 2 (TORC2) has conserved roles in regulating cytoskeleton dynamics and cell migration and has been linked to cancer metastasis. However, little is known about the mechanisms regulating TORC2 activity and function in any system. In Dictyostelium, TORC2 functions at the front of migrating cells downstream of the Ras protein RasC, controlling F-actin dynamics and cAMP production. Here, we report the identification of the small GTPase Rap1 as a conserved binding partner of the TORC2 component RIP3/SIN1, and that Rap1 positively regulates the RasC-mediated activation of TORC2 in Dictyostelium. Moreover, we show that active RasC binds to the catalytic domain of TOR, suggesting a mechanism of TORC2 activation that is similar to Rheb activation of TOR complex 1. Dual Ras/Rap1 regulation of TORC2 may allow for integration of Ras and Rap1 signaling pathways in directed cell migration.

The Interferon (IFN) family of cytokines are produced in direct response to virus infection and they constitute the first line of defence against virus infection by inducing hundreds of interferon stimulated genes (ISGs) which act in concert to establish the so-called “antiviral state”. Influenza A viruses and parainfluenza virus type 5 (PIV5) are both small negative strand RNA viruses that must circumvent their hosts’ interferon (IFN) response for replication. However, the ways in which these viruses interact with the IFN system are very different. Although PIV5 replication is initially severely impaired in cells in a pre-existing IFN-induced antiviral state, it manages to overcome the antiviral state by targeting an essential component of type I IFN signalling, STAT1, for degradation. Thus the cells cannot maintain the antiviral state indefinitely without continuous signalling. Consequently, the virus resumes its normal replication pattern after 24-48 hours post-infection. In clear contrast, influenza virus fails to establish its replication in the majority of infected cells (90-95%) with a pre-existing IFN-induced antiviral state, although a few cells are still able to produce viral antigens. To further investigate how influenza virus interacts with cells in a pre-existing IFN-induced antiviral state, I have used in situ hybridization to follow the fate of input and progeny genomes in cells that have, or have not, been treated with IFN prior to infection. Here I show for the first time that IFN pre-treatment blocks the nuclear import of influenza A virus genome, which prevents the establishment of virus replication, but this can be overcome by increasing multiplicities of infection. Of those IFN-induced antiviral molecules, human MxA is an essential component of the IFN-induced antiviral state in blocking influenza virus genome import, as this block can be abolished by lentivirus-mediated knockdown of MxA. I also show that in cells constitutively expressing MxA the viral genome still manages to be transported into the nucleus, indicating that MxA might require an unidentified IFN-induced factor to block nuclear import of the influenza virus genome. These results reveal that IFN exerts its action at an early stage of virus infection by inducing MxA to interfere with the transport of viral genome into the nucleus, which is the factory for viral RNA production.

Yeung, Barry Ho Sing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 137-154). / Abstracts in English and Chinese. / Abstract --- p.i / 論文摘要 --- p.iv / Acknowledgements --- p.vii / Publications based on work in this thesis. --- p.ix / List of abbreviations --- p.x / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Dorsal root ganglion cells --- p.1 / Chapter 1.1.1 --- Primary sensory neurons --- p.1 / Chapter 1.1.2 --- Non-neuronal cells --- p.3 / Chapter 1.1.2.1 --- Satellite glial cells --- p.3 / Chapter 1.1.2.2 --- Schwann cells --- p.6 / Chapter 1.2 --- Peripheral sensitization --- p.8 / Chapter 1.3 --- Neuron-glia interactions --- p.9 / Chapter 1.4 --- Aim of Thesis --- p.11 / Chapter Chapter 2 --- "Materials, media, buffers and solutions" --- p.13 / Chapter 2.1 --- Materials --- p.13 / Chapter 2.2 --- "Culture media, buffer and solutions" --- p.19 / Chapter 2.2.1 --- Culture media --- p.19 / Chapter 2.2.2 --- General culture buffers and culture plate coating reagents --- p.19 / Chapter 2.3 --- Antibodies used for identifying DRG cells --- p.23 / Chapter 2.3.1 --- Primary antibodies --- p.23 / Chapter 2.3.2 --- Secondary antibodies --- p.23 / Chapter Chapter 3 --- Methods --- p.24 / Chapter 3.1 --- Preparation of DRG cell cultures --- p.24 / Chapter 3.2 --- Preparation of neuron-enriched and glial cell cultures --- p.25 / Chapter 3.3 --- Immunocytochemistry --- p.26 / Chapter 3.4 --- Immunohistochemistry --- p.27 / Chapter 3.4 --- Determination of [3H]cAMP production in DRG cells --- p.28 / Chapter 3.4.1 --- Principle of assay --- p.28 / Chapter 3.4.2 --- Loading DRG cells with [3H]adenine --- p.28 / Chapter 3.4.3 --- Column preparation --- p.28 / Chapter 3.4.4 --- Measurement of [3H]cAMP production in DRG cells --- p.29 / Chapter 3.4.5 --- Data analysis --- p.30 / Chapter Chapter 4 --- Identification of DRG cells in dissociated cultures --- p.31 / Chapter 4.1 --- Introduction --- p.31 / Chapter 4.2 --- Aim of study --- p.34 / Chapter 4.3 --- Results --- p.35 / Chapter 4.3.1 --- Identification of DRG cells in isolated cultures --- p.35 / Chapter 4.3.2 --- Activation and proliferation of glial cells in isolated cell cultures --- p.36 / Chapter 4.3.3 --- Identification of glial cells in cultures --- p.38 / Chapter 4.3.4 --- Modification of staining methods --- p.40 / Chapter 4.3.5 --- Immunohistochemistry to identify DRG cells in DRG slices --- p.42 / Chapter 4.3.6 --- Comparison of antibody staining in whole DRG and isolated DRG cells --- p.44 / Chapter 4.4 --- Discussion --- p.44 / Chapter 4.5 --- Summary --- p.53 / Chapter Chapter 5 --- Characterization of GPCRs in isolated DRG cultures --- p.69 / Chapter 5.1 --- Introduction --- p.69 / Chapter 5.1.1 --- G-protein coupled receptors --- p.69 / Chapter 5.1.2 --- Pharmacological characterization of prostanoid receptors on DRG cells --- p.73 / Chapter 5.1.3 --- Gs- and Gi/o-coupled GPCRs in DRG cells --- p.75 / Chapter 5.1.3.1 --- Gs-coupled GPCR: β-adrenoceptors --- p.76 / Chapter 5.1.3.2 --- Gs-coupled GPCR: CGRP receptors --- p.79 / Chapter 5.1.3.3 --- Gi/o-coupled GPCR: α2-adrenoceptors --- p.82 / Chapter 5.1.3.4 --- Gi/o-coupled GPCR: Cannabinoid receptors --- p.85 / Chapter 5.1.3.5 --- Gi/o-coupled GPCR: 5-HT1Areceptors --- p.88 / Chapter 5.1.3.6 --- Gi/o-coupled GPCR: opioid and opioid-receptor-like 1 receptors --- p.90 / Chapter 5.2 --- Aims of study --- p.93 / Chapter 5.3 --- Results --- p.94 / Chapter 5.3.1 --- Characterization of prostanoid receptors in isolated DRG cells --- p.94 / Chapter 5.3.2 --- Characterization of CGRP receptors in isolated DRG cells --- p.96 / Chapter 5.3.3 --- Investigation of the effect of CGRP8.37 on CGRP responses --- p.97 / Chapter 5.3.4 --- Characterization of β1-adrenoceptors in isolated DRG cells --- p.97 / Chapter 5.3.5 --- Characterization of β2-adrenoceptors in isolated DRG cells --- p.98 / Chapter 5.3.6 --- Identification of β-adrenoceptor subtype mediating isoprenaline-stimulated responses.. --- p.99 / Chapter 5.3.7 --- Characterization of α2-adrenceptors in isolated DRG cells --- p.100 / Chapter 5.3.8 --- Characterization of cannabinoid 1 receptors in isolated DRG cells ... --- p.100 / Chapter 5.3.9 --- Characterization of cannabinoid 2 receptors in isolated DRG cells --- p.101 / Chapter 5.3.10 --- Characterization of 5-HT1A receptors in isolated DRG cells --- p.101 / Chapter 5.3.11 --- Characterization of μ-opioid receptors in isolated DRG cells --- p.102 / Chapter 5.3.12 --- Characterization of opioid-receptor-like 1 receptors in isolated DRG cells --- p.102 / Chapter 5.3.13 --- Effect of nerve growth factor on DRG cells --- p.103 / Chapter 5.4 --- Discussion --- p.106 / Chapter 5.5 --- Summary --- p.114 / Chapter Chapter 6 --- Conclusion and further studies --- p.134 / References --- p.137

The overall aim of this thesis is to investigate strategies to aid in the measurement of G-protein coupled receptor (GPCR) activity for high-throughput screening and sensing applications. GPCRs are cell surface receptors which have seven membrane spanning domains. They are the largest family of membrane proteins in the human genome and are involved in a number of physiological and pathophysiological pathways. They are the most widely targeted protein family for therapeutics being the target for over 30% of the currently available prescription drugs (Jacoby et al. 2006). For this reason commercial interest and investment into compound screening using these receptors as targets is of high importance in lead drug discovery. Additionally, the extensive ligand range of the GPCR superfamily, which includes light, odorants/ volatiles, neurotransmitters and hormones, make them an attractive biological recognition element in biosensor applications. This thesis demonstrates the functional expression of the H1-histamine, M2-muscarinic and α₂ₐ-adrenergic receptors of the G-protein coupled receptor family, along with their associated G-proteins (Gα, Gβ and Gγ). Expression was achieved using the Sf9/baculovirus expression system. The G-proteins were successfully incorporated into an assay system using time-resolved fluorescence resonance energy transfer (TRFRET). TR-FRET was used in order to create a homogeneous assay format capable of monitoring GPCR activation through the movement of the G-protein subunits. Fluorescence changes in the TR-FRET assay indicated a change in distance between the Gα subunit and Gβγ dimer. The separation of the Gα subunit and the Gβγ dimer after activation resulted in a significant decrease in TR-FRET measurement. The homogeneous set-up of the TR-FRET assay could potentially be adaptable to an array based format. This thesis describes the capture of vesicles containing functional GPCRs onto a solid substrate via the specific interaction between complementary oligonucleotides. GPCR presence and function within the immobilized vesicles, was demonstrated using fluorescent ligands. Further to this, alternative lipid hosts (to the vesicles), known as cubosomes, were introduced. When tagged with an oligonucleotide, these cubosome particles were also shown to immobilize site specifically onto a complementary oligonucleotide surface. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1369537 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2009

The overall aim of this thesis is to investigate strategies to aid in the measurement of G-protein coupled receptor (GPCR) activity for high-throughput screening and sensing applications. GPCRs are cell surface receptors which have seven membrane spanning domains. They are the largest family of membrane proteins in the human genome and are involved in a number of physiological and pathophysiological pathways. They are the most widely targeted protein family for therapeutics being the target for over 30% of the currently available prescription drugs (Jacoby et al. 2006). For this reason commercial interest and investment into compound screening using these receptors as targets is of high importance in lead drug discovery. Additionally, the extensive ligand range of the GPCR superfamily, which includes light, odorants/ volatiles, neurotransmitters and hormones, make them an attractive biological recognition element in biosensor applications. This thesis demonstrates the functional expression of the H1-histamine, M2-muscarinic and α₂ₐ-adrenergic receptors of the G-protein coupled receptor family, along with their associated G-proteins (Gα, Gβ and Gγ). Expression was achieved using the Sf9/baculovirus expression system. The G-proteins were successfully incorporated into an assay system using time-resolved fluorescence resonance energy transfer (TRFRET). TR-FRET was used in order to create a homogeneous assay format capable of monitoring GPCR activation through the movement of the G-protein subunits. Fluorescence changes in the TR-FRET assay indicated a change in distance between the Gα subunit and Gβγ dimer. The separation of the Gα subunit and the Gβγ dimer after activation resulted in a significant decrease in TR-FRET measurement. The homogeneous set-up of the TR-FRET assay could potentially be adaptable to an array based format. This thesis describes the capture of vesicles containing functional GPCRs onto a solid substrate via the specific interaction between complementary oligonucleotides. GPCR presence and function within the immobilized vesicles, was demonstrated using fluorescent ligands. Further to this, alternative lipid hosts (to the vesicles), known as cubosomes, were introduced. When tagged with an oligonucleotide, these cubosome particles were also shown to immobilize site specifically onto a complementary oligonucleotide surface. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1369537 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2009

[Truncated abstract] The calcium-sensing receptor (CaR) is a G protein-coupled receptor that can respond to changes in extracellular calcium and plays an integral role in calcium homeostasis. Later studies revealed that the CaR was stimulated by not just calcium, but a diverse range of stimuli and that activation of the receptor regulated a host of different biological processes. The CaR is linked to these cellular responses via the various signalling pathways initiated by the receptor. Recent yeast two-hybrid studies have identified a number of accessory proteins that, through their interaction with the intracellular tail of the CaR, are able to regulate important functional aspects of the receptor, including its signalling and degradation. We hypothesised that many more proteins that bind to the CaR-tail await identification, especially since most of the previous studies used the yeast two-hybrid system to screen cDNA libraries generated from tissues that are important to whole body calcium homeostasis, such as the parathyroid gland and kidney. In order to identify novel binding partners of the CaR, which may affect its function, particularly in biological processes that might be unrelated to calcium homeostasis, our laboratory performed a yeast two-hybrid screen of an EMLC.1 mouse pluripotent haemopoietic cell line library using the intracellular tail of the human CaR as bait. This screen revealed a large number of

The overall aim of this thesis is to investigate strategies to aid in the measurement of G-protein coupled receptor (GPCR) activity for high-throughput screening and sensing applications. GPCRs are cell surface receptors which have seven membrane spanning domains. They are the largest family of membrane proteins in the human genome and are involved in a number of physiological and pathophysiological pathways. They are the most widely targeted protein family for therapeutics being the target for over 30% of the currently available prescription drugs (Jacoby et al. 2006). For this reason commercial interest and investment into compound screening using these receptors as targets is of high importance in lead drug discovery. Additionally, the extensive ligand range of the GPCR superfamily, which includes light, odorants/ volatiles, neurotransmitters and hormones, make them an attractive biological recognition element in biosensor applications. This thesis demonstrates the functional expression of the H1-histamine, M2-muscarinic and α₂ₐ-adrenergic receptors of the G-protein coupled receptor family, along with their associated G-proteins (Gα, Gβ and Gγ). Expression was achieved using the Sf9/baculovirus expression system. The G-proteins were successfully incorporated into an assay system using time-resolved fluorescence resonance energy transfer (TRFRET). TR-FRET was used in order to create a homogeneous assay format capable of monitoring GPCR activation through the movement of the G-protein subunits. Fluorescence changes in the TR-FRET assay indicated a change in distance between the Gα subunit and Gβγ dimer. The separation of the Gα subunit and the Gβγ dimer after activation resulted in a significant decrease in TR-FRET measurement. The homogeneous set-up of the TR-FRET assay could potentially be adaptable to an array based format. This thesis describes the capture of vesicles containing functional GPCRs onto a solid substrate via the specific interaction between complementary oligonucleotides. GPCR presence and function within the immobilized vesicles, was demonstrated using fluorescent ligands. Further to this, alternative lipid hosts (to the vesicles), known as cubosomes, were introduced. When tagged with an oligonucleotide, these cubosome particles were also shown to immobilize site specifically onto a complementary oligonucleotide surface. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1369537 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2009

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. "June 2008" Includes bibliographical references.

Thesis (M.S.)--Mississippi State University. Department of Biological Sciences. / Title from title screen. Includes bibliographical references.