Description du projet
Révéler les mécanismes moléculaires de l’ubiquitination
Le système d’ubiquitine est une voie cellulaire hautement régulée et complexe responsable de la dégradation des protéines par le protéasome. Elle implique la fixation d’une petite protéine appelée ubiquitine à des protéines cibles par des enzymes ubiquitine ligase E3 spécifiques. Le système de transfert de l’ubiquitine est apparu comme une cible médicamenteuse intéressante pour intervenir sur des protéines spécifiques associées à la maladie. Financé par le Conseil européen de la recherche, le projet CsnCRL entend faire la lumière sur les mécanismes moléculaires responsables de la régulation du processus d’ubiquitination et notamment celui des ligases E3. Les chercheurs mèneront des études structurales et fonctionnelles avancées à l’aide de techniques telles que la cristallographie aux rayons X et la cryomicroscopie électronique. Outre l’apport d’informations fondamentales sur l’ubiquitination, les résultats du projet contribueront à décoder le comportement des complexes à plusieurs sous-unités.
Objectif
Specificity in the ubiquitin-proteasome system is largely conferred by ubiquitin E3 ligases (E3s). Cullin-RING ligases (CRLs), constituting ~30% of all E3s in humans, mediate the ubiquitination of ~20% of the proteins degraded by the proteasome. CRLs are divided into seven families based on their cullin constituent. Each cullin binds a RING domain protein, and a vast repertoire of adaptor/substrate receptor modules, collectively creating more than 200 distinct CRLs. All CRLs are regulated by the COP9 signalosome (CSN), an eight-protein isopeptidase that removes the covalently attached activator, NEDD8, from the cullin. Independent of NEDD8 cleavage, CSN forms protective complexes with CRLs, which prevents destructive auto-ubiquitination.
The integrity of the CSN-CRL system is crucially important for the normal cell physiology. Based on our previous work on CRL structures (Fischer, et al., Nature 2014; Fischer, et al., Cell 2011) and that of isolated CSN (Lingaraju et al., Nature 2014), We now intend to provide the underlying molecular mechanism of CRL regulation by CSN. Structural insights at atomic resolution, combined with in vitro and in vivo functional studies are designed to reveal (i) how the signalosome deneddylates and maintains the bound ligases in an inactive state, (ii) how the multiple CSN subunits bind to structurally diverse CRLs, and (iii) how CSN is itself subject to regulation by post-translational modifications or additional further factors.
The ERC funding would allow my lab to pursue an ambitious interdisciplinary approach combining X-ray crystallography, cryo-electron microscopy, biochemistry and cell biology. This is expected to provide a unique molecular understanding of CSN action. Beyond ubiquitination, insight into this >13- subunit CSN-CRL assembly will allow examining general principles of multi-subunit complex action and reveal how the numerous, often essential, subunits contribute to complex function.
Champ scientifique
- natural sciencesearth and related environmental sciencesgeologymineralogycrystallography
- natural sciencesphysical sciencesopticsmicroscopyelectron microscopy
- natural sciencesbiological sciencesgeneticsmutation
- natural sciencesbiological sciencesbiochemistrybiomoleculesproteinsenzymes
- natural sciencesbiological sciencesmolecular biologystructural biology
Programme(s)
Thème(s)
Régime de financement
ERC-ADG - Advanced GrantInstitution d’accueil
4058 Basel
Suisse