EPFL BioE Talks SERIES "Lipid Driven Nanodomains Are Fluid and Interleaflet Coupled"


Event details

Date 15.11.2021 16:0017:00  
Speaker Prof. Martin Hof, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague (CZ)
Location Online
Category Conferences - Seminars
Event Language English

It is a fundamental question whether sphingomyelin (SM)- and cholesterol (Chol)- driven nanodomains exist in cells and in model membranes. Studies on model membranes revealed SM and Chol driven micrometer-sized liquid-ordered domains. Although the existence of such microdomains has not been proven for the plasma membrane, such lipid mixtures have been used as a model system for ‘rafts’ [1]. On the other hand, super resolution results indicate that the plasma membrane might organize into nanocompartments. However, due to the limited resolution of those techniques the characterization of such nanodomains is still missing.

In this lecture, a combination of Förster resonance energy transfer and Monte Carlo simulations (MC-FRET) [2] identifies directly 10 nm large nanodomains in liquid-disordered model membranes composed of lipid mixtures containing SM and Chol [3]. That MC-FRET approach can determine the sizes and concentrations of nanodomains down to 2 nm and enables studying the nanodomain inter-leaflet coupling [4,5]. Combining MC-FRET with solid-state wide-line and high resolution magic angle spinning NMR [3] as well as with fluorescence correlation spectroscopy [6] we demonstrate that these nanodomains containing hundreds of lipid molecules are fluid  and interleaflet coupled [3,4].

Addition of GM1 ganglioside, a molecule which forms already at concentrations of 2% fluid nanometer sized clusters in phosphatidylcholine bilayers [7,8], leads to growth of those SM/ Chol nanodomains while preserving the fluidity. We examine the importance of the bulky ganglioside headgroup to the nanoscopic segregation of gangliosides by reducing the size of the headgroup from ganglioside GM1, to ganglioside GM2 and GM3. In this way, we identified the key molecular factors that drive nanoscopic segregation of gangliosides in lipid bilayers [9].

[1]  M. Cebecauer et al. Chem Rev, 118, (23), 11259-11297,2018
[2]  R. Šachl et al. Biophys. J., 101, L60-L62, 2011
[3]  A. Koukalová et al. Scientific Rep. vol. 7 p. 5460, 2017.
[4]  I. Vinklarek et al, J Phys Chem. Lett 10, 2024–2030, 2019
[5]  M.J. Sarmento et al Frontiers in cell and developmental biology, 8, 284, 2020
[6]  R. Šachl et al. J. Phys. D 49 189601, 2016
[7]  R. Šachl et al. BBA- Mol. Cell Res. 1853, 850-857, 2015.
[8]  M. Amaro et al. Angew. Chem. vol. 55 p. 9411-9415, 2016.
[9]  M.J. Sarmento et al Biophys J., accepted.

• Scientific education
   2009 Full Professor for Physical Chemistry named by the Czech President
   2006 Doctor of Science (DSc.), Academy of Sciences of the Czech Republic (CAS)
   1999 Habilitation at the Faculty for Chemistry and Pharmacy of the Julius-Maximilians-University Würzburg
   1990 Dissertation in Physical Chemistry at the University Würzburg (“with excellence (1.0)”); Advisor: Prof. Dr. F. W. Schneider
   1987 "Diplom-Chemiker" at the University Würzburg; (“with excellence (1.0)”)
• Current positions
   5/2017- Director of the J. Heyrovský Institute of Physical Chemistry; CAS
   2001- Lecturer and PhD advisor at
   Faculty of Nature Sciences of the Palacky University Olomouc (Czech Republic),
   Faculties of the Charles University Prague
   Faculties of the Czech Technical University in Prague, and
   Biological Faculty of the South Bohemian University Ceske Budejovice (Czech Republic)
   2000- Senior Scientist at the J. Heyrovský Institute; Start-up of own scientific group
• Previous positions
   2007-4/2017 Vice-Director of the J. Heyrovský Institute, CAS
   2006-4/2017 Head of the Department of Biophysical Chemistry at that Institute
   1997-1999 Scientist at the J. Heyrovský Institute, CAS
   1997-1999 Assistant Professor at the Department of Physical Chemistry, Würzburg
   1996 Visiting scientist at the University of Patras, Greece (Prof. P. Lianos)
   1993-1995 Liebig Fellow at the Department of Physical Chemistry/Charles University Prague (Prof. V. Fidler)
   1991-1993 Postdoctoral Fellow at the University of North Carolina at Chapel Hill (USA) (Prof. N. L. Thompson) and University Würzburg (Prof. F. W. Schneider)

As a consequence of the ongoing Covid-19 pandemic, in-person attendance of this seminar is subjected to some constraints:
  • Maximum number of participants is limited to 80 (2/3 of room SV1717's nominal capacity): first come, first served!
  • Valid COVID certificate and ID, required to enter the meeting room, will be checked at the entrance
  • Face masks are mandatory for everyone in the seminar room (excepted the speaker while presenting).
Thank you warmly for your understanding!

Alternatively, the seminar can also be followed via Zoom web-streaming:
Zoom link (with one-time registration for the whole series) for attending remotely: https://go.epfl.ch/EPFLBioETalks

Instructions for 1st-year Ph.D. students who are under EDBB’s mandatory seminar attendance rule:
IF you are not attending in-person in the room, please make sure to
  1. send D. Reinhard a note before noon on seminar day, informing that you plan to attend the talk online, and
  2. be signed in on Zoom with a recognizable user name (not a pseudonym making it difficult or impossible to be identified).
Students attending the seminar in-person should collect a confirmation signature after the talk - please print your own signature sheet beforehand (71 kB pdf available for download here).

Practical information

  • Informed public
  • Registration required