CANCELED: Bimolecular reactions in the cell membrane exhibit switch­like behavior with respect to diffusivity and molecular reach

Friday, February 22, 2019 - 1:30pm to 2:45pm
WXLR A 113


Samuel Isaacson
Associate Professor
Department of Mathematics and Statistics
Boston University


Many T cell receptors have long, unstructured cytoplasmic tails that contain tyrosine sites. These sites can serve as regulators of receptor activation when phosphorylated or dephosphorylated, while also serving as docking sites for cytosolic enzymes. We develop a particle­-based stochastic reaction­-diffusion model to study the combined diffusion of individual receptors within the cell membrane, and chemical reactions between proteins bound to receptor tails. The model suggests a switch­like behavior in the dependence of the fraction of activated receptors on both receptor diffusivity, and on the molecular reach at which two receptor tails can interact. A simplified, analytically  solvable model is developed to approximate the more complicated multi­particle system, and used to illustrate how the switch­like behavior appears.