Morgan Chabanon
Laboratoire EM2C, CNRS, CentraleSupélec, Université Paris-Saclay

“Dynamic modeling of protein-membrane interaction during collagen export”

Cellular lipid bilayers are found to display incredibly diverse shapes and dynamics, both at the plasma membrane surrounding the cell and at membrane bound organelles. These structures are intrinsically linked to the organelle biological functions. Therefore understanding the origin of these structures and the cause of their disruption from soft matter physics point of views is of great interest in cellular biology and medicine.

In this talk we will focus on the chemo-mechanical mechanisms allowing cells to export collagen fibers, the main components of skin and other biological tissues. Surprisingly, the export machinery for collagen relies on COPII proteins, which typically form 80nm spherical membrane carriers, much smaller than the 200nm long collagen fibers. Recently, a membrane protein called TANGO1 has been shown to organize into rings around COPII coats, suggesting it plays a key role in the formation of large carriers. We developed a continuum dynamic model that couples membrane bending and in-plane protein transport, and tested possible routes of formation of collagen bulky carriers. We found that TANGO1 plays a key role in modulating the formation of collagen carriers by stabilizing the forming bud and controlling membrane tension at the export site, in accordance with experimental evidences.