Justin Watkins, Ph.D.
Wake Forest University
Alan Jones, Ph.D.
I received my PhD in Biology from Wake Forest University under the mentorship of Dr. Gloria Muday. My thesis explored how the hormone ethylene alters plant development and gene expression in guard cells. Guard cells function to control the opening of stomata, pores on the leaf surface that facilitate gas exchange and water loss. Modulation of these pores is essential for plant adaptability to drought stress. Using fluorescent probes and confocal microscopy, I discovered a novel role for ethylene in modulating redox signaling in guard cells of Arabidopsis and tomato leaves, altering drought tolerance.
As a SPIRE scholar, I am a member of Alan Jones’s lab studying signal transduction in plants. A hallmark characteristic of signal transduction is the ability for a signal molecule to modulate a wide range of responses. How a signal mediates such a diverse array of outputs and how these response pathways are integrated with other inputs remains a fundamental question in biology and in many aspects of human health. I am investigating these questions in the Jones Lab through studying heterotrimeric G protein signaling in plants. G protein signaling is one mechanism that plant and human cells utilize to create signal amplification and diversification in response to a wide variety of stimuli. A better understanding of how the G protein signaling pathway is regulated will provide deeper mechanistic insights into how external stimuli modulate cell physiology and gene expression.
One aspect of this research project focuses on elucidating the phosphatases involved in regulating G protein signaling. In plants, the resting state of G protein signaling is maintained by the receptor-like protein Regulator of G Signaling (RGS1). Kinases on the plasma membrane phosphorylate RGS1 in response to stimuli such as pathogen invasion, hormone signaling, and glucose. Phosphorylation of RGS1 is necessary and sufficient to induce G protein signaling; however, little is known about the phosphatases that regulate this process. Preliminary results from in vitro binding assays have uncovered candidate phosphatases than may interact and dephosphorylate RGS1, inhibiting G protein signaling.