The plasma membrane as early mechanotransducer in T lymphocytes
In the lymphatic organs of vertebrates, circulating T lymphocytes seek traces of pathogenic antigens by sensing the environment. Intriguingly, mechanics is central to this game of hide-and-seek: the very first step of immune recognition. Recognition is now understood as an amplification of the molecular-scale response of the T cell receptor (TCR)-antigen bond, to a cell-scale reaction. While traditionally the focus has been on cytoskeletal forces, based on recent evidence, this project will explore the cell plasma membrane (PM) as a mechanical amplifier. We will quantitatively image PM of T cells, genetically modified to modulate cholesterol, while they engage with antigen-presenting surfaces prepared using techniques of soft nanofabrication. Whereas all the experimental tools and protocols are in place, the key challenge will be quantitative imaging, innovative analysis and interpretation.
Cell Plasma Membrane, Quatitative microscopy, T lymphocyte
The overall objective is to explore the role of plasma membrane in early T-cell mechano-transduction. We ask: does adhesion and membrane topography, mapped using reflection interference contrast microscopy (RICM), correlate with traction force maps (TFM) and how this is modified by T cell PM cholesterol content? Is TCR-cluster recruitment to nano-clusters of antigen cholesterol dependent? Does PM organisation depend on substrate softness? Does that impact PM topography (RICM)? Or exerted forces (TFM)?
The candidate should have a PhD in Physics, biophysics or biology, with an aptitude for experimental work and data analysis. (S)he will do experiments, which will include substrate preparation, cell preparation and advanced microscopy, as well as extensive image analysis. Preference will be given to candidates with prior experience with cells, and/or advanced optical microscopy. Basic skills in mathematics and computer programming are essential.
Is this project the continuation of an existing project or an entirely new one?
This project is a new collaboration between partners 1 (KS) and 2 (YH). It is based on the expertise of KS (Physicist, model membranes, patterned substrates, optical microscopy, mechanosensing) and YH (Immunologist, T lymphocyte membrane, optical microscopies), who share a common interest in ImmunoBioPhysics from molecular to cellular scales. Partner 3 (PP) brings his own unique expertise (Biophysicist, T cell mechanics, force measurement) and will act as a bridge between the two main partners, having collaborated with both (KS: PhD ending April 2022, funded by Doc2AMU, 3 common publications; and YH: PhD defended in 2018, financed by Labex INFORM, 6 common publications)..
2 to 5 references related to the project
- Force-induced growth of adhesion domains is controlled by receptor mobility, Smith,et al Proc. Nat. Acad. Sc. USA 105:6906-11 (2008).
- Single-cell immuno-mechanics: rapid viscoelastic changes are a hallmark of early leukocyte activation. Zak, A., et al. Biophysical Journal, 120(9), 1692-1704 (2021).
3 main publications from each PI over the last 5 years
KS: Fenz et al. Nature Physics, 13, 906–913 (2017).
Alameddine et al. Nano Lett. 17(7): 4284–4290 (2017).
Wahl et al. PNAS 116(13) 5908-5913 (2019)
YH: Blouin et al., Cell 166(4): p. 920-934 (2016).
Chouaki-Benmansour et al. Scientific reports, 2018. 8(1): p. 4966.
Raducka-Jaszul et al. Membranes, 11(7), 498 (2021)..
PP: Sadoun, A., et al. Scientific reports, 11(1), 1-15 (2021).
Zak, A., et al. Biophysical Journal, 120(9), 1692-1704 (2021).
Ndao et al. Frontiers in cellular and infection microbiology, 10, 207 (2020).