Lund University, Sweden
“Interactions between membrane-associated molecules – from aggregating proteins to immune-cell contacts”
Wednesday, May 23, at 13:15
The interaction between membrane-associated molecules is responsible for the proper function of many biological processes, such as the formation of stable cell contacts and receptor signaling. These interactions can take place between proteins within the same cell membrane, but also between proteins on the surface of two contacting cells. I will here give an overview of the research my group is doing in characterizing these interactions with a special aim of better understanding the molecular mechanisms underlying the formation of protein clusters or aggregates on the cell membrane and how the strength of the molecular interactions across contacting immune cells can control immune-cell signaling.
We have in order to achieve this developed various new methods and techniques to study these phenomena. This includes a technique we call hydrodynamic trapping, which uses the liquid flow out of a micropipette to accumulate molecules coupled to a lipid bilayer . Using this we can locally increase the concentration of membrane-associated molecules by orders of magnitude and characterize the molecular forces between them. We have also developed a new method to measure weak interactions between interacting proteins on contacting cells by replacing one of the cells with a model cell membrane and studying the interaction with living cells using fluorescence microscopy. This has allowed us to investigate how different molecules distribute in immune-cell contacts and to quantify the binding strength between key membrane proteins on the contacting immune cells [2,3]. I will finally discuss how the latter is currently used by us to better understand the molecular mechanisms of how our immune system can separate between our own cells and foreign pathogen.
 Jönsson P et al., Proc. Natl. Acad. Sci. U.S.A., 109, 10328-10333 (2012).
 Chang VT et al., Nature Immunol, 17, 574-582 (2016).
 Jönsson P et al., Proc. Natl. Acad. Sci. U.S.A., 113, 5682-5687 (2016).
Best regards on behalf of Adam Cohen Simonsen