Intellectual Merit: Cells adapt to their environment through modulation of intracellular signaling pathways that cause changes in gene expression. Enzymes that modify proteins directly are key components of signaling pathways. Lysine acetylation is a type of modification conserved from bacteria to humans. Recent studies have revealed its widespread occurrence on proteins in eukaryotic cells, but its roles in signaling are poorly understood, and so are the roles of enzymes that regulate it, lysine acetyltransferases (KATs) and lysine deacetylases (KDACs). Present understanding of the functions of acetylation, KATs, and KDACs has been dominated by studies of histone acetylation, which facilitates gene expression. Thus, KATs and KDACs are considered to promote and impair RNA synthesis, respectively. However, recent studies have shown that KDACs are concentrated in regulatory regions of active genes, that they are recruited to genes by factors that promote RNA synthesis, and that their inhibition or depletion can cause repression of gene expression. In addition, many regulatory proteins are acetylated, yet the functional impact is largely uncharacterized. In the few cases that have been studied, acetylation has been found to either impair or enhance protein function. Thus KDACs may indeed facilitate transcription. This project addresses this possibility using glucocorticoid receptor (GR) signaling as a model system. Like other members of the nuclear receptor family, the GR binds directly to target genes and assembles protein complexes that facilitate gene expression. This study will determine the impact of KDAC inhibition or depletion on GR-induced complex assembly at GR target genes, identify the KDACs that cooperate with GR to activate gene expression, assess the acetylation state of key proteins, and define the impact of that acetylation on protein function at GR target genes. Once completed this project will generate new and unconventional models for the role of acetylation in GR signaling and provide a more comprehensive view of the contributions of KDACs and non-histone protein acetylation to regulation of gene expression through signaling.
Broader Impacts: The research project will provide research and training opportunities for graduate students, undergraduates, and high school students in the course of generating critical new knowledge of a fundamental post-translational modification. The incorporation of undergraduates and high school students into the research team will provide mentoring experiences to the graduate students and serve under-represented groups through several University of Arizona programs that provide scientific research and training opportunities to undergraduates and high school students from these groups. All students will be trained to develop critical thinking, problem-solving, and communication skills, which will enable them to pursue careers that contribute to strengthening and diversifying the national scientific workforce. The research findings will be broadly disseminated through publication in peer-reviewed, open-access journals and presentations at national meetings and other public-speaking opportunities.
