This study focuses on the role of protein modification in responses of marine organisms to a variety of environmental stressors. The characteristics of such responses may determine tolerance limits to these stressors, and are largely controlled by protein catalysts that govern many cellular processes. This research will determine whether a specific protein modification is involved in responses to environmental stress by marine mussels, and assess its role in setting tolerance limits to heat stress, oxygen limitation and ocean acidification. A change in protein abundance is a key indicator of how cells protect themselves from structural damage and readjust cellular processes to maintain cellular function in a changing environment. Protein synthesis and degradation are costly processes; therefore other means of controlling protein function have evolved. Protein function can be greatly modified by the addition of a number of chemical groups after protein translation (i.e., post-translational modifications or "PTMs"). Recently, it has been shown that a broad range of cellular functions are regulated by enzymes called acetylases and deacetylases, which add or remove an acetyl group to or from proteins. Sirtuins, one class of deacetylases, are now known to affect many cellular processes that link the cell cycle to energy metabolism and oxidative stress. Preliminary observations by the principal investigator using two independent proteomic methods demonstrated that heat stress changes the abundance of sirtuins, and that 18-55% of proteins are affected by sirtuin-induced deacetylation during heat stress in gill tissue of two blue mussel congeners (Mytilus) that differ in thermal tolerance, a heretofore unknown scope of activity for any PTM.
This study will assess the global role of (de-)acetylation during the cellular response to heat stress, oxygen limitation and ocean acidification, evaluate the importance of (de-)acetylation in setting tolerance limits, and establish the contribution of various deacetylases to patterns of protein acetylation. This research will help establish the general importance of (de-)acetylation as a key regulator of protein function in response to environmental stress in marine organisms.
Undergraduate and graduate students, as well as visiting scholars will be trained in proteomic techniques, including mass spectrometry. The principal investigator has collaborated with a number of colleagues to build a community around environmental proteomics, has organized a symposium on the topic at a recent conference, and is developing a two-week training course on proteomic techniques. He is disseminating his research in a number of public lectures on adaptation of organisms to rapidly changing environmental conditions. His work is providing insights into mechanistic determinants of species, distribution patterns, and is contributing to the goal of predicting the effects of climate change.
