Reference : PhD Jean Cavarelli
Post-translational methylation of arginine is a widespread epigenetic modification found in eukaryotes that is catalyzed by the protein arginine methyltransferases (PRMTs). The PRMT family has been the focus of many biological researches and at least nine members of the PRMT family (PRMT1 to PRMT9) have been identified in mammalian cells.
PRMT are divided into four major classes (type I to type IV) depending on the chemistry of methyl-arginine they generate. Type I and type II PRMT, the two most populated classes have
been extensively studied. PRMTs are modular proteins, varying from 320 to 970 amino acids and sharing a common catalytic methyltransferase domain to which additional domains are added thus conferring structural and functional specificity to each PRMT. Many studies have now shown that several PRMTs are crucial molecules involved in many processes essential to cell life.
As deregulation of these processes may be implicated in the pathogenesis of different diseases such as human cancers, PRMTs represent potential new targets for which compounds can be developed and that can be exploited to provide new therapies against cancer. PRMTs are usually parts of larger functional complexes including other modulator/adaptor proteins and little is known about how proteins function dynamically within those macromolecular assembly.
As many of those complexes are transient assemblies their studies at the structural level represent one of the big challenges of today’s structural biology. Understanding the mechanism of action of PRMTs at the atomic scale is therefore crucial both for fundamental biology and pharmacological applications.
Thanks to extensive research by many teams several dozen crystal structures of PRMTs have been determined either free or in complex with cofactor analogue.
Following the work done in our team on understanding the structure-function relationship of PRMT2, PRMT4/CARM1, PRMT6 and PRMT7, the subject of the thesis work proposed here will focus on the study of another poorly characterized PRMT, named here PRMTx. The detail of the project is confidential.
The project will combine structural, biophysical and biochemical studies to understand how PRMTx recognizes and bind its substrates (including inhibitors) or co-regulators. The thesis project will contain 3 tasks: structural and functional studies of PRMTx alone or in complexes with small substrates (co-factors or inhibitors); (ii) discovery of PRMTx specific inhibitors by structure-based drug design; (iii) structural studies of complexes involving PRMTx and other epigenetic co-regulators. Structure determination will be done using X-ray crystallography and cryo-Electron Microscopy.The team will benefit from a technical environment offering state of the art equipment for integrated structural biology (FRISBI infrastructure, IGBMC).
The PhD student will be involved in all steps of the structural biology process: cloning, expression, purification of the protein targets, crystallizations, sample preparations, and structure determination by X-ray crystallography and/or cryoelectron microscopy and biological interpretations. Several homologues of the target protein will be used in parallel and different with expression systems to increase the chances of producing samples suitable for structure determination. The team will use the technological tools available through the Structural Biology and Genomics Technology Platform (SBGT) of IGBMC (FRISBI and INSTRUCT platform).
The candidate will be familiar with the techniques used in molecular biology to clone, express and purify proteins. Knowledge of 3D protein structure, X-ray
crystallography or cryo-electron microscopy, biophysical methods to characterize macromolecular complexes and molecular modeling will be appreciated. Enthusiasm for working in a multi-disciplinary environment is required. Knowledge of spoken and written French is not a requirement.
Expertises Structural bioinformatics.
From gene to structure at different scale of resolution
(integration of X-ray crystallography and cryo-electron microscopy). Protein expression, purification and biophysical characterization. Structure determination and characterization, Drug design and molecular modeling
Application Deadline : Nov. 1, 2018