Proteins on membranes
Our lab has a strong track record in studying protein interactions with biological membranes, with a particular focus on using supported lipid bilayers and surface sensitive techniques. This knowledge combined with our lab’s microscopy and QCM-D instrumentation, has contributed to a number of local collaborations at Umeå University. When our colleagues are searching for biophysical expertise to complement their research, we are happy to step in. We help to design and execute the experiments that meet their needs. These collaborations have resulted in several publications in recent months.
In a collaboration with the laboratory of Sun Nyunt Wai (Department of Molecular Biology), we have studied a cytolytic bacterial toxin from Vibrio cholerae, MakA. We have used our biophysical tools to look how MakA interacts with membranes of a complex lipid composition. A first publication in PNAS shows that MakA oligomerizes into complexes at the membrane surface when together with two additional proteins (MakB and MakE). This leads to pore formation and eventually cell lysis. Our second publication in this collaboration was in Elife. It demonstrates that MakA alone can induce tube-like structures in acidic endosomal compartments, thereby revealing a new mode of action by a secreted bacterial toxin.
A second collaboration with the laboratory of Richard Lundmark (Department of Integrative Medical Biology) focuses on caveolae. Caveolae are small plasma membrane invaginations which mediate membrane tension, signaling cascades, and lipid homeostasis. An essential caveola-associated protein is Cavin1. Our recent paper in PNAS provides a more detailed understanding on how Cavin1 inserts into the membrane and thereby contributes to remodeling planar membranes into highly curved structures.