Robert Augustine

Biography: Dr. Augustine, Assistant Professor with the Department of Biology at Colby College

COBRE pilot project:  Genetic and Proteomic Characterization of Moss SUMO Signaling During Heat Stress.

Abstract
Cells must rapidly respond to environmental stresses to mitigate damage and promote survival. One conserved molecular mechanism for stress protection in eukaryotes is the rapid attachment of small ubiquitin-related modifier (SUMO) to numerous target proteins within minutes of a wide array of stresses. However, the mechanism(s) by which SUMO signaling confers stress protection requires elucidation, and is complicated by the vast number of stress-induced SUMOylated proteins and variable outcomes that this modification may impart on the modified target—especially its role in maintaining protein solubility to prevent proteotoxic stress. The objective of this proposal is to develop the moss Physcomitrium patens as a powerful model for understanding SUMO’s role in heat stress protection by generating genetic and proteomic tools, and to develop heat-stress assays that separate SUMO’s role in signaling from its role as a proteotoxic stress protection agent. The central hypothesis is that stress-induced SUMOylation serves as a signal that re-wires the chromatin landscape, alters the transcriptome, and promotes survival. The rationale for optimizing heat-stress assaying conditions is to utilize physiologically-relevant conditions that are lethal to SUMO system mutants, are enriched in SUMO signaling targets, and will reduce the size and complexity of SUMO proteome lists. The rationale for using moss to understand SUMO biology is that this model is rapid for dissecting gene function due to its ease-of-transformation, amenability to reverse-genetic approaches, propensity for homologous recombination, and predominantly haploid life cycle where mutant and knock-in lines manifest immediately within the transformed generation. Furthermore, moss tissues can be rapidly scaled up for biochemical approaches by vegetative propagation. The specific aims proposed here develop the necessary groundwork for characterizing the moss SUMO system and its role in stress signaling by: 1) generating and functionally characterizing a collection of mutant and knock-in lines, optimizing heat-stress assaying conditions, and generating antibodies for detection of moss SUMO, and 2) purifying and identifying SUMO conjugates by proteomic methodologies under ambient and heat-stress conditions. By leveraging the advantages of the moss system, I anticipate the rapid generation of tools that will serve as the framework for testing the central hypothesis that SUMO signals and re-wires the genome in response to heat stress.

Relevance to health
Given SUMOylation’s universal protective role against environmental, genotoxic, and proteotoxic stresses, this work should inform our understanding of how SUMO signaling promotes survival against stress in humans such as recovery from low-oxygen environments that occur during strokes, and how its dysregulation leads to pathologies such as cancer and neurodegenerative diseases.