Dr. Kennelly investigates the development of the mechanisms by which living organisms sense and respond to changes in their circumstances and surroundings.
Life is a dynamic process. Hence, in order to survive and prosper, all living organisms require the capacity to monitor and respond to changes in both their internal state and external environment. Living organisms use several mechanisms for carrying out signal transduction, the process by which the stimulation of some sensor is translated into a physiological response through a change in the function of one or more proteins. One of the most prominent of these mechanisms is protein phosphorylation, wherein sensors activate enzymes called protein kinases that seek out and attach phosphate groups to protein targets. The attachment of a phosphate group acts as a molecular switch that, in essence, turns the target protein "on". Enzymes called protein phosphatases can remove the phosphate group to return a target protein to its "off" state. It is estimated that one-third of all proteins in the human body are controlled by a phosphate switch. Improper functioning of these switches has been implicated in a variety of human pathologies, including cancer, diabetes, cystic fibrosis, and Alzheimer's disease. Our laboratory uses a simple model organism to study the role of protein phosphorylation in the control of basic cellular processes. By studying an ancient progenitor of higher organisms, we are able to trace the origins and development of the complex network of protein phosphorylation events that imbue humans and other animals with their sophisticated capacity to monitor and respond to a wide range of stimuli. Specifically, we have been able to identify the protein kinases responsible for the regulation of two essential cellular processes, gene expression and protein synthesis. Using proteomic and genomic techniques we intend to identify the proteins phosphorylated by these protein kinases and use this information to identify their counterparts in animals. Identification of these phosphorylated proteins will provide basic information to be applied to understanding the specific defects associated with a variety of human diseases.