Genetic Regulation of Stress Responses at the Endoplasmic Reticulum

Western Washington University, Bellingham WA

Investigators

Abstract

PROJECT SUMMARY Protein quality control allows cells to respond to environmental and molecular stressors and to remove proteins that can lead to disease or death. The Endoplasmic Reticulum (ER) is sensitive to protein misfolding and overcrowding. ER-associated degradation (ERAD) is a defense against protein overcrowding, which can increase cell stress. However, ERAD be balanced so that toxic proteins, with the potential to harm, are degraded, but functional proteins are not. Using a multicellular model organism (C. elegans) we will investigate how ERAD mechanics impact organismal level outcomes during environmental and cellular stress. Upregulation of the ERAD complex protein, VIMP (VCP Interacting Membrane Protein, SelenoS), is an early marker associated with ER stress, but VIMP’s precise biochemical role in facilitating ERAD is unclear. Consistent with the mission of the National Institute of General Medical Sciences, the central objective of this proposal is to uncover how the ERAD protein VIMP regulates stress responses at the ER. C. elegans, is a well-established model for studying ER stress and protein homeostasis and it is amenable techniques that include fluorescence microscopy, CRISPR- Cas modification, transgenesis, and protein biochemistry. We will use a combination these diverse technical approaches to test the hypothesis that ceVIMP regulates gene transcription to control ER stress responses in and between cells. The specific aims of this project are 1) to determine the cellular and subcellular sites of ceVIMP action, 2) to define the roles of two isoforms of ceVIMP in organismal biology and stress response, and 3) to dissect ceVIMP’s participation in cell biological and biochemical pathways. We will address these aims using complimentary genetic, biochemical, and microscopy approaches. We will establish the pattern and requirements for ceVIMP expression, examine if differential expression of ceVIMP isoforms help animals respond to ER stress, and identify the protein interactions that ceVIMP makes under non-stressed and stressed conditions. Undergraduate students will participate in all aspects of this project, including experiment design, data collection, and dissemination of results. These experiments will yield novel mechanistic insights into how ERAD is regulated to maintain cellular and organismal health by maintaining homeostasis at the endoplasmic reticulum. We will investigate cell-autonomous and non-autonomous interactions to complement existing evidence that inter-tissue communication drives balanced responses to stress. Importantly, findings from these experiments will likely be applicable to complex mammalian systems because of the high degree of genetic conservation between C. elegans and mammals, including humans. This is particularly important because diseases of protein misfolding and aggregation, such as cystic fibrosis and Huntington’s disease affect impact the health of diverse cell types in ways that affect the many aspects of human physiology.