MuLife: Fluorescence microscopy imaging to reveal the molecular architecture of living organisms.

OVERVIEW

MuLife is a microscopy platform dedicated to fluorescence imaging. Equipped with state-of-the-art instruments, MuLife can handle a wide range of applications, going from high-resolution molecular imaging to dynamic imaging for life sciences. The service we propose include advice and follow-up on projects from sample preparation to image acquisition, practical and theoretical training on the equipment, technical assistance for the use of equipment, and temporary data storage and transfer to a server dedicated to platform users. We also benefit from a strong expertise in single filaments imaging in vitro and in cellulo molecular imaging, traction stresses measurement by «traction force microscopy» and dynamic «laser patterning». The R&D work performed on the platform relies on a technology watch approach, through which, in particular, the platform is able to acquire and test innovative equipment before it becomes commercially available.

EXPERTISE AND SERVICES

• Visualize dynamic events rapidly in several dimensions
• Characterize fixed or dynamic molecular structures using evanescent wave imaging
• Co-localize molecules using high-resolution molecular imaging
• Quantify the dynamic protein renewal by targeted illumination : FRAP, photoconversion
• Study the mechanical properties of a structure by applying laser photoablation
• Measure cellular traction stresses using «Traction Force Microscopy»
• Modify the cellular environment in a controlled manner thanks to laser-induced dynamic patterning

RESSOURCES AND EQUIPMENT

• 1 Zeiss LSM880 confocal microscope equipped with a Fast AiryScan detector
• 1 Nikon spinning disk confocal microscope equipped with a laser photo-ablation module
• 1 Nikon multimodal TIRF equipped with a targeted illumination module ; equipped with a laser photo-ablation module ; compatible with super-resolution (PALM)
• 1 Olympus inverted fluorescence microscope to observe live samples in phase-contrast or epifluorescence
• 1 cell culture laboratory with a BSL2 containment level
• 1 data-analyses station

HOW TO SUBMIT A PROJECT

The platform is located on the CEA-Grenoble site and accessible to the academic and industrial scientific community. The platform intervenes in the form of collaborations or services (invoicing of total cost). All requests for access must be sent to the platform’s technical manager under the supervision of a project manager, who will specify the requirements for the project (objectives of the experiment, type of sample, particularities linked to the experiment, desired period of access to the platform, name of the user, etc.). These needs will be assessed by the platform’s scientific and technical managers, and then training for the user operating the project will be planned on the appropriate equipment(s) according to its availability. Once the training has been completed, the user will be given access to: 1/ the microscope – 2/ the booking calendar – 3/ the data transfer server.

EXAMPLE

Li Y., Compressive forces stabilize microtubules in living cells, Nature Materials 2023. DOI: 10.1038/s41563-023-01578-1

Microtubules are rigid polymers of the cytoskeleton that alternate phases of growth and shrinkage, giving them exceptional dynamic properties. In their study, Yuhui and collaborators aimed at studying the link between this microtubule dynamics and their mechanical properties. To address this question, the authors used a stretching-device to characterize the response of microtubules to cycles of compressive forces in living cells. By using a combination of fast imaging of microtubule-associated components on the spinning disk and high-resolution imaging on the Airyscan confocal of the imaging facility, they found that microtubules become distorted, less dynamic and more stable under stretching. He additionally showed that this mechano-stabilization depends on the microtubule-associated protein CLASP2, which relocates from the end of the microtubules to their deformed shaft. This process seems to be instrumental for cell migration in confined spaces. Overall, these results demonstrate that microtubules in living cells have mechano-responsive properties that allow them to resist and even counteract the forces to which they are subjected, being a central mediator of cellular mechano-responses.