The edge of a Cell, a living fabric: When Physics meets Biology at the surface of living cells

Founder's Day 2023 talk by Prof Satyajit Mayor, NCBS

The plasma membrane of an animal cell is a lipid bilayer sandwiched in between the extracellular matrix at the outside and the cortical cytoskeleton at the inside of the cell, demarcating the edge of the cell. It also serves as the site of information transfer between the outside and the inside of the cell. It has been fifty years since Singer and Nicolson proposed a model to synthesize many of the biophysical properties and organizational characteristics of the plasma membrane, however, efforts to understand the structure and consequently function of the plasma membrane have a long history. In my talk I will survey this history as well as provide an evolutionary perspective on the origins of this remarkably complex fabric made up of many different lipid species and proteins, draped over a cortical actin mesh. It has only been recently recognized that engagement with this dynamic cortex results not only in the control of the shape of the cell and diffusion of membrane components, but also the local composition of this membrane. I will discuss a new model, the active actin membrane composite model of the plasma membrane which accounts for how local composition at the meso-scale may be regulated by the active mechanics of the underlying cytoskeleton. In my talk, I will show how this feature provides a cell the capacity to integrate both chemical and physical cues to fine tune its information processing systems.