EAPSI: Constriction of Cell Membranes by Helix-Shaped Rods

Mcdargh Zachary A, Pittsburgh PA

Investigators

Abstract

When material needs to be transported around the cell, the cell membrane forms a bud surrounding the material. This is a step in nearly all biological processes. The protein dynamin is responsible for detaching these buds from the body of the membrane by forming a helix-like shape around the neck of the bud, constricting it. The details of how dynamin does this, though, are somewhat mysterious. Does dynamin use fuel from its environment to tighten around the neck of the bud? How small can dynamin constrict the radius of the neck? These questions cannot be answered without understanding how the membrane responds to constriction forces from a helix-shaped rod. This project will focus on developing mathematical models to investigate this process. This work will be performed at the Beijing Normal University in collaboration with Professor Zhanchun Tu, renowned for his theory of membrane elasticity using differential forms. Many models have been proposed likening dynamin's function to that of a garrote, ratchet, or spring. In this project Guven's auxiliary variables approach will be used to put past models on a firmer mechanical footing. A thermodynamic model of dynamin as a molecular motor will also be investigated, with special regard to such a motor's maximum power and efficiency. This NSF EAPSI award supports the research of a U.S. graduate student and is funded in collaboration with the Ministry of Science and Technology of China.