IMPReSs

The main mission of IMPReSs (Integral Membrane Proteins Research and Services) is to develop and propose original and robust bioproduction methodologies aimed at facilitating the structural and functional studies of proteins in solution, in particular membrane proteins (MPs).

Our global expertise is focused on the bioproduction of eukaryotic MPs. It is notably based on the mastery of a particularly efficient eukaryotic expression system adapted to the mass production of MPs, the methylotrophic yeast Pichia pastoris. It also relies on a wide range of methodologies dedicated to the preparation and characterization of MPs isolated in different controlled membrano-mimetic environments (detergents, amphiphilic polymers, liposomes and lipid nanoparticles).

Our activities are divided into two areas:

1/ We make our validated procedures and tools available to the entire academic and private scientific community, in the form of service or research contracts validated by the CNRS. In order to best meet users' projects, the service offer is divided into fully modular thematic activities ranging from cloning the gene of interest to purifying the corresponding protein.

This offer is detailed in the Services section below.

2/ Through various methodological research projects, we strive to develop and diversify our know-how on bioproduction issues with a dual objective:

- Explore new methodological avenues intended to facilitate the study of MPs in solution.

- Increase our expertise and our service offer.

Current projects are summarized in the Research & Development tab of the site.

We offer our partners different types of services and benefits:

• Cloning

Cloning of the gene of interest can be handled from DNA provided by the client (cDNA or plasmid DNA) or by a service provider (synthetic gene in particular). The platform has a panel of standard expression vectors adapted to the expression systems used, which can be customized according to needs (affinity tags, cleavage sequences, etc.). Classical restriction/ligation cloning approaches are usually used to obtain recombinant vectors.

• Expression testing

Different expression systems are routinely used within the platform for the production of membrane proteins (MPs) and cytosoluble proteins, in particular the Pichia pastoris and Escherichia coli systems, as well as various mammalian cell lines. Through a feasibility study, the production of the protein of interest can thus be tested in the most suitable expression system(s) available.

In the case of the Pichia pastoris expression system, the use of the Yeastern Blot technique developed on the platform allows screening for the best expressing clones in a 96-well format.

• Protein sample production and preparation

Proteins of interest are produced in shaken flasks up to a volume of 10 liters of medium. For larger volumes, cultures in 3 to 5-liter bioreactors are also possible. In the case of PMs, proteins can be supplied in the form of membrane preparations, obtained by differential ultracentrifugation after cell lysis.

• Protein purification

The platform has access to four automated purification chains (Äkta Pure, Äkta Purifier type), as well as a complete panel of affinity, ion exchange and size exclusion chromatography columns and resins. Depending on the needs, purification by more specific methods can also be set up.

In the case of membrane proteins, a screening of extraction and purification conditions is carried out in order to best meet the needs of each protein and each project (buffer composition, detergent screening, detergent exchanges, protein processing, chromatographic methods, etc.).

• Reconstitution of PMs into lipid particles

After purification, when conditions allow it, the reconstitution of PMs in a membrano-mimetic environment (proteoliposomes, lipid nanoparticles, etc.) can be carried out to address the issues of stability of PMs in solution.

• Sample characterization

At each step, different biochemical analyses are used for characterizing the protein samples (electrophoresis, immunodetection, size exclusion chromatography, etc.). Mass spectrometry analyses can also be carried out in collaboration with our colleagues from PCBIS and LSMBO (IPHC, Strasbourg). When available, activity tests can be performed at each stage of production for advanced protein characterization. The platform is notably fully equipped and accredited to perform radioactive tests such as ligand binding or transport assays, including in 96-well format. Fluorimetric tests and SPR interaction assays are also possible.

IMPReSs has been involved for several years in teaching and leading practicals on the theme of bioproduction within the ESBS (Strasbourg School of Biotechnologies) and the EASE (European Aseptic and Sterile Environment) training center.

As a member of various national and international scientific networks dedicated to the study of membrane systems and their associated proteins, we have been participating for several years in various research projects in the field of production and analysis of recombinant proteins. We have thus accumulated solid know-how valued by numerous publications and 4 patents that concretely illustrate our skills.

In terms of activities, nearly 200 collaborative research and service projects have been carried out at IMPReSs since its establishment in 2012. These projects are carried out both on behalf of private partners (Avacta, Calixar, Domain Therapeutics, Eurofins, NovAlix, NMRTech, Sanofi, Servier, Synthelis, etc.), but also within the framework of various academic collaborations at the local (IBMC, IBMP, ICS, IGBMC, IPHC-LSMBO, Pharma School), national (University of Avignon; CBMN Bordeaux; IBS Grenoble; IBCP and ISA Lyon; IBMM and IGF Montpellier; Institut Curie, Institut Pasteur and UPMC Paris) and international (Ghent University, BE; Instituto Butantan, BR; Copenhagen University, DK; Scripps RI, USA) levels.

Renaud Wagner
UAR3286 PCBIS
Plateforme IMPReSs
300, Boulevard Sébastien Brant
CS 10413
67412 ILLKIRCH cedex

Tél : 03 68 85 47 31
e-mail : esbs-impress[at]unistra.fr