RUI: Electrophilic Modulation of the Heat Shock Response System

Dickinson College, Carlisle PA

Investigators

Abstract

With this award, the Chemistry of Life Processes Program in the Division of Chemistry is funding Professor Rebecca Connor of Dickinson College to investigate how stress affects individual cells in tissues and organs. It is thought that one way cells protect themselves against environmental stresses such as toxins is through a process known as the heat shock response. This project is investigating how certain stress-inducing molecules interact with proteins involved in the heat shock response. It is known that the body's ability to make use of this protective system decreases with age, so the work is also giving deeper insight into how the cellular aging process occurs. This work is having a broader impact on the understanding of basic biological processes that help to maintain good health. Knowledge gained from this work will be useful for a number of fields, including toxicology. The work is having a further broad impact on the training of the next generation of scientists through the many undergraduates at this institution who are participating in the research project. In this project, studies are being carried out to determine how parthenolide and similar electrophilic molecules chemically affect the cellular heat shock response system (HSR) of cells through covalent modification of the chaperone proteins Hsp70 and Hsp90 and the transcription factor, Hsf1. Peptide enrichment of affinity tagged parthenolide derivatives combined with MALDI-TOF/TOF analysis identifies covalently-adducted amino acids. Mutation of these residues as well as covalent adduction sites previously published in the literature are being used in combination with kinetic binding, protein refolding, co-immunoprecipitation and electrophoretic shift assays to build a complete picture of the effect of modification on heat shock protein (Hsp) function. Both the identification of specific amino acid residues involved in the activation of the heat shock protein response by electrophilic molecules and the quantification of the specific effects on binding affinity, chaperone activity and DNA binding of the Hsps found in the heat shock complex are helping clarify how the heat shock response is controlled. The sensor mechanisms of the heat shock complex are important for the cellular response to environmental toxins and other molecules, as well as cellular senescence.