Two students graduated this past December with their doctoral degrees in Biological Sciences. Anjali Gupta and Priyanka Sivadas both studied under Dr. Pinfin Yang. Dr. Gupta is currently a Postdoctoral Fellow at Albert Einstein Medical School, and Dr. Sivadas is a Postdoctoral Fellow at the University of Southern California.
John Brenner, a student of Dr. Alison Abbott, has just successfully defended his doctoral thesis entitled: “Genetic Identification of developmental Pathways Regulated by Conserved microRNAs in Caenorhabditis elegans”, and is graduating with his Ph.D. in May. Brenner will start his Postdoctoral Fellowship at Washington University in St. Louis this summer.
The Department of Biological Sciences is grateful to announce that Andrew Karls is the first recipient of the Dr. Catherine Grotelueschen Scholarship, given by Dr. Catherine Grotelueschen and her husband Mr. James Grotelueschen. Dr. Grotelueschen is an alumnus of our Biological Sciences Department, earning her Master’s degree in 1975. The endowment will provide scholarship support towards the summer stipend for a graduate student in the Biological Sciences Department. Andrew Karls’ research examines different ways that neurons regulate voltage-gated calcium channels. In neurons, the concentration of intracellular calcium is much lower when compared to extracellular concentrations. Thus, entry of calcium ions can serve as a switch, turning on or off a variety of cellular processes. One potential way these calcium channels are regulated is by G-protein coupled receptors, such as the GABAB receptor. While much is known about how these receptors can inhibit calcium channels, Andrew’s work specifically focuses on how GABAB receptor activation leads to calcium current enhancement. This summer, Andrew will begin experiments designed to provide detailed information about the particular calcium channel isoform involved in calcium current enhancement, as well as describe kinetic and physiological differences between these specific isoforms. This work has implications in how seizure disorders such as epilepsy are treated early in life.
The Department of Biological Sciences periodically receives funding from the Denis J. O’Brien Fellowship Fund for financial assistance in the form of a summer stipend. This year’s winner is Adam Lietzan.
Adam’s research project uses protein X-ray crystallography and steady-state kinetic analyses to detail the poorly characterized mechanism of coordination between the two remote active sites in Pyruvate carboxylase (PC), a multi-site biotin-dependent enzyme. His structural studies have revealed features that promote the efficient coordination of catalysis between distinct active sites and have unveiled potentially important roles for previously unrecognized residues in each of the enzyme active sites.
Pyruvate carboxylase serves as a paradigm for catalysis in multi-enzyme systems. PC transfers a carboxybiotin intermediate generated in the biotin carboxylase (BC) domain to a pyruvate acceptor substrate in the carboxyl transferase (CT) domain. This summer, Adam’s research goals consist of kinetically characterizing mutant forms of PC in order to demonstrate the contribution of various amino acids to forming the biotin-binding pocket in the CT domain. Enzymatic assays will be utilized to describe alterations in the catalytic and coupling efficiency between the two distinct active sites. These experiments will provide a detailed description of plasticity in the CT domain during catalysis while presenting insights into a mechanism for coordinating distinct active sites in a model multi-enzyme system.