Modeling the Cell Biology of the Heat Shock Response of Barley Aleurone Cells

When heat shocked, plant cells distribute their energy to make a very different set of proteins than when at normal temperatures. Along with other secretory proteins, α-amylase is particularly affected by heat shock. This protein is responsible for digesting the starchy food stores contained in the endosperm of a barley seed. These starchy nutrients comprise the largest part of the food store that allows the seed to germinate. When barley is heat shocked, the cells′ production of α-amylase and other secretory proteins is largely reduced and a set of heat shock proteins that repair damaged proteins is produced. This change in protein synthesis is the result of selective destabilization of the mRNAs encoding α-amylase and other secretory proteins. In addition, the endoplasmic reticulum (ER) upon which these secretory protein mRNAs are translated into proteins undergoes major structural and compositional changes. The purpose of this project is to create and test a mathematical model to analyze how these elements interact to influence α-amylase production while the cell is under heat stress. Our current model and simulations are able to capture the impact of different temperature regimes and levels of fluidity on α-amylase synthesis and are in good qualitative agreement with the experimental data.