Termin: 23.11.2009 Uhrzeit: 17:00 ( c.t. ) - 18:30 ( c.t. ) ( Montag )
Spatiotemporal aspects of GPCR signalling visualized by fluorescence microscopy
Kolloquium
| Referent/in: | Prof. Dr. Moritz Bünemann Institut für Pharmakologie und Toxikologie Philipps-Universität Marburg |
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| Inhalt: | In order to better understand important physiological processes regulated by G protein-coupled receptors (GPCRs), we analyzed kinetics of GPCR activation, assembly with G proteins as well as kinetics of G protein activation in living cells. Fluorescence resonance energy transfer have been developed and adapted to analyze both conformational movements of proteins and protein/protein interactions. Using these novel techniques we studied conformational movements underlying agonist-mediated activation of different GPCRs in single living cells. Solving the kinetics of receptor activation we observed activation time constants typically between 40-80 ms. Interactions of receptors with their G proteins were also studied by FRET. Furthermore FRET assays were developed to study activation of Gi/o, Gq and Gs proteins in living cells. Our results question the dogma of complete separation of G protein subunits upon activation. In cases of robust receptor expression the activation of G proteins was significantly slower than receptor /G protein interaction, suggesting to be the first speed limiting step in the receptor signal transduction pathway. FRET is great to solve dynamics of protein/protein interaction, however it does not provide information about the stability of protein/protein interactions under steady state conditions. Receptor dimerization has been an emerging topic in pharmacology over the last decade. In order to address the stability of receptor dimerization we developed a novel assay, which is based on mobility measurements in membranes of living cells. Using these assays remarkable differences were found between highly homologous b1 and b2 adrenergic receptors. |
| Öffentliche Veranstaltung: | Ja |
| Ort: | Pharmazeutisches Institut |
| Adresse: | Gerhard-Domagk-Str.3 |
| Raum: | 2 |
| Weitere Informationen: | http://www.pharma.uni-bonn.de |
| Veranstalter: | Fachgruppe Pharmazie |
