Extra-translational Function of Transfer RNA as Regulators of Cellular Processes

Type of Award: Catalyst
Date Awarded: January 2014
Award End Date: December 2015
Amount Awarded: $ 199,998.00
PI(s): Tao Pan, PhD, UChicago; Marsha Rosner, PhD, UChicago; Hidayatullah G. Munshi, MD, NU;

Abstract: Communications between cellular processes are essential in homeostasis and in cellular response to environmental change. Protein synthesis is a major process that consumes a vast amount of materials and energy in the cell. Hence, coordination of protein synthesis activity with other cellular processes such as cell cycle control, histone modification, membrane trafficking and so on should be crucial for cell physiology. We have discovered recently that tRNAs may serve as a major class of communicators in the cell. We found that tRNAs bind to a wide array of cellular proteins such as the mitogen-activated protein kinase kinase (MEK), histone methyltransferase 1, GTP-binding protein SAR1a, farnesyl-transferase, glutathione synthetase, and phosphoenolpyruvate carboxykinase; none was known previously to interact with any nucleic acids. We hypothesize that tRNA binding regulates the activity of these proteins in response to the translation activity in the cell. When translation activity is high, only a small amount of tRNA is available, and these tRNA-protein interactions are present only at low levels. When translation activity decreases, more tRNA becomes available to increase the level of these tRNA- protein interactions in order to up- or down-regulate the cellular processes these proteins participate in. Here, we propose to test this hypothesis for the MEK-tRNA interaction in vitro and in non-tumorigenic and pancreatic cancer cells. Aim 1 will validate MEK-tRNA interaction in non- tumorigenic and pancreatic cancer cells. Aim 2 will test MEK binding to tRNA in vitro, and generate MEK mutants that disrupt binding. Aim 3 will test the physiological effect of such MEK mutants in 3D cell cultures. Our results should reveal a potential new paradigm for cellular communications involving RNA-protein interactions.