Ph.D. position (M/F) in biochemistry of membrane proteins

Job Description

Thesis Subject

Mitochondria are primarily known for their role in ATP synthesis. The enzyme responsible is the F1Fo-ATP synthase, a multi-subunit protein complex present in the inner mitochondrial membrane. It forms a rotating nano-motor that couples proton translocation across the inner mitochondrial membrane to the generation of ATP from ADP and Pi in the matrix. The assembly of this edifice is a very complex and relatively poorly understood process. TMEM70 is one of the recently identified ATP synthase assembly factors. Mutations in TMEM70 are associated with neonatal mitochondrial encephalo-cardiomyopathy caused by a very strong decrease in the amount of ATP synthase.
We have constructed and used different cellular models (RNA interference, CRISPR/Cas9, patient fibroblasts) that allowed us to discover the target of TMEM70 which turned out to be the central subunit of the ATP synthase membrane turbine, the c subunit formed by 2 transmembrane helices linked by a loop in the matrix. The c subunit is synthesized in the cytosol and then imported into mitochondria. A poorly understood sequence of events involving TMEM70 leads to its insertion into the inner membrane so that both ends are in the intermembrane space, and to the assembly of eight copies into a ring that is then inserted into the forming ATP synthase.
To better understand this sequence of events and the involvement of TMEM70, as well as the pathogenic mechanisms of its mutations, the project aims to use in vitro and in organello experiments to study the insertion and assembly of c-subunit ring with TMEM70 and other recently identified partners. The project will involve in vitro protein production and reconstitution in nanodiscs as well as in organello import of protein precursors into isolated mitochondria, approaches for which we have already made the proof of concept.
These studies will allow us to better understand the molecular mechanisms involving TMEM70 but also to better understand the pathogenic mechanisms of mitochondrial encephalo-cardiomyopathies associated with TMEM70 mutations.

We will utilize newly developed in vitro research tools that have already been validated in the laboratory (in vitro protein production; nanodisc reconstitution; in organello import of radio-labeled precursors; NiNTA and FLAG protein purification; biochemical protein analyses by electrophoresis: SDS-PAGE, BN-PAGE, 2D, Western blot), as well as on the numerous tools available in the laboratory (cell lines, antibodies, constructs), and on our expertise in the study of mitochondria (bioenergetics, enzymes, complexes, membrane proteins, etc.). The project will also benefit from the expertise of collaborators at the IBGC (standard and expanded fluorescence microscopy and electron microscopy) and the CBMN (nanodiscs, cryo-electron microscopy).

The project is funded by the ANR in France and the DFG in Germany (PRCI). This thesis project will be conducted primarily at the IBGC in collaboration with the CBMN in Bordeaux (Dr. Marie-France Giraud), where some of the experiments will be carried out. The laboratory of our collaborator at LMU Munich will also participate in this project, and regular exchanges are planned.

The candidate is expected to show a very high motivation for the study of membrane proteins and multi-protein complexes, and be in the second year of a master's program with a specialization in biochemistry. Previous training with cultured mammalian cells is welcome but not mandatory.

Your Work Environment

The Institute of Cellular Biochemistry and Genetics (IBGC) is a research center from the CNRS and the University of Bordeaux located on the Carreire campus in Bordeaux. The IBGC is composed of 12 teams with a strong identity centered on research in fundamental biology and on particular topics such as cell division, genome maintenance, chromosome segregation, mitochondria and energy metabolism. The diversity of the model organisms used (the yeasts S. cerevisiae and S. pombe, the fungus P. Anserina, the fly D. melanogaster and the nematode C. elegans as well as rodent (mouse and rat) and human models) and the complementarity of the know-how in cell biology, genetics and biochemistry are its strengths.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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