|Assistant Professor of Chemistry
D. Scott Witherow is active in pedagogical research in the field of biochemistry and molecular biology. He has published a book entitled Molecular Biology Techniques: A Classroom Laboratory Manual (Elsevier Academic Press), as well as authored publications in pedagogical journals. As the biochemical sciences are a readily-evolving field, the way in which they are taught needs to be continually changed and updated as well. Both in classroom and laboratory settings, students should be challenged to learn and apply knowledge and skills consistent of a modern-day biochemical scientist. The research in this area involves developing and assessing new strategies to effectively prepare students for their scientific future.
Heterotrimeric G Protein Signaling
Research in Witherow’s lab focuses broadly on heterotrimeric G protein signaling. Signal transduction through this mechanism involves binding of a ligand to a receptor that is on the surface of the cell (a G protein-coupled receptor, or GPCR), which subsequently leads biochemical changes inside the cell, such as enzyme activation and gene regulation. Many fundamental processes such as vision, muscle contraction, nerve cell signaling, taste and smell are all regulated by G protein signaling pathways. Consequently, over 50% of all FDA-approved therapeutics currently target proteins involved in GPCR-mediated signaling, making this a very active field of study. A general outline and schematic for heterotrimeric G protein signaling is shown in the figure to the right.
Currently, there are two primary projects that are being studied in the lab. The first involves delineating the signaling that is regulated by the unique G protein subunit, Gβ5. Whereas most G protein β subunits bind to Gγ subunits (see the figure above), Gβ5 does not do so in vivo. Instead, it binds to a specific subfamily of regulators of G protein signaling (RGS) proteins (Witherow et al, 2002). The function of these Gβ5-RGS dimers has remained elusive. Another study has shown that they form complexes with RGS7 binding protein (R7BP) (Martemyanov, 2005, J Biol Chem. 280:5133-6), another protein little is currently known about. To attempt to put add more pieces to the puzzle and elucidate the function of these proteins, the yeast two-hybrid genetic screen is being employed to look for additional interacting proteins. Using this experiment, one protein (for instance, R7BP) can be screened against millions of other proteins in a single experiment to look for other interacting proteins. From there, experiments to confirm the interactions in cellular systems are employed. Finally, physiologic experiments are performed in mammalian cells to ascertain the functional consequences of newly discovered interactions.
The second project currently being initiated involves the study of G protein signaling in corals. Corals are important in maintaining the health of aquatic ecosystems. Corals are prevalent in reefs, providing habitats for fish, lobster, and numerous other organisms. Unfortunately, many species of corals are endangered, falling victim to changes in environmental factors, as well as coral-specific diseases. This research project involves the characterization of novel G protein components from corals commonly found in Florida and Caribbean reefs. It has been shown previously that corals contain GPCRs (Anctil, et al, 2007, Gene 392:14-21), but little is known about their activation and downstream signaling. This research project would aim to identify and characterize these proteins using in vitro systems.
The research projects described above are geared towards undergraduates. These projects give biochemistry students a chance to apply their classroom knowledge. Instead of doing problems from textbooks, students can devise, perform, interpret, and troubleshoot experiments aimed at solving new problems that have never before been solved. Undergraduate researchers in the lab would perform a wide variety of standard biochemical and molecular biological techniques, such as PCR, DNA cloning, protein expression and purification, western blotting, cell culture, and others. While most of the work students will be performed at UT, external collaborations are possible for students whose research requires it. Modern science is largely a collaborative process. To solve complex problems, scientists with different backgrounds and areas of expertise frequently team up to make the best use of the resources available, and the research performed here is no different. Students performing research in the lab should expect to think independently, apply classroom knowledge to practical applications, and learn how to do real world science. It is a challenging process that can be both fun and rewarding at the same time!
If you wish to learn more about Witherow’s research or discuss research opportunities in his lab, please contact him by email at firstname.lastname@example.org or stop by his office (Science Wing 204).
For an example of a poster recently presented by an undergraduate student working with Dr. Witherow, click here.
Relevant publications by Witherow in the G protein fieldD. Scott Witherow and Vladlen Z. Slepak (2004) “Biochemical purification and functional analysis of complexes between the G protein subunit Gβ5 and regulators of G protein signaling (RGS) proteins” Meth Enzymol. 391:149-162
D. Scott Witherow and Vladlen Z. Slepak (2003) “A novel kind of G protein heterodimer: the Gβ5-RGS complex” Receptors Channels. 9(3):205-12.
D. Scott Witherow, Steven C. Tovey, Qiang Wang, Gary B. Willars, and Vladlen Z. Slepak (2003) “Gβ5-RGS7 inhibits Gαq-mediated signaling via a direct protein-protein interaction” J Biol Chem. 278(23):21307-13.
Oliver N. Hausmann, Wen-Hui Hu, Tal Keren-Raifman, D. Scott Witherow, Qiang Wang, Konstantin Levay, Beata Frydel, Vladlen Z. Slepak, and John R. Bethea (2002) “Expression of RGS7 Protein in Neurons, Microglia and Macrophages following Spinal Cord Injury in Rats” Eur J Neurosci. 15(4):602-12.
Tal Keren-Raifman, Amal K. Bera, Dror Zveig, Sagit Peleg, D. Scott Witherow, Vladlen Z. Slepak, and Nathan Dascal (2001) “Expression levels of RGS7 and RGS4 proteins determine the mode of regulation of the G protein activated K+ channel and control regulation of RGS7 by Gβ5” FEBS Lett. 492(1-2):20-8.
D. Scott Witherow, Qiang Wang, Konstantin Levay, Jorge L. Cabrera, Jeannie Chen, Gary B. Willars, and Vladlen Z. Slepak (2000) “Complexes of the G protein subunit Gβ5 with the regulators of G protein signaling RGS7 and RGS9. Characterization in native tissues and in transfected cells.” J Biol Chem. 275(32):24872-80
Witherow’s biochemistry pedagogical publicationsHeather B. Miller, D. Scott Witherow, and Susan Carson. “Student Learning Outcomes and Attitudes when Biotechnology Lab Partners are of Different Academic Levels” (manuscript submitted).
Susan Carson, Heather B. Miller, and D. Scott Witherow. Core Technologies in Molecular Biology: A Classroom Laboratory Manual, Third Edition. Academic Press, London, UK, 2012.
D. Scott Witherow and Susan Carson (2011) “A laboratory-intensive course on the experimental study of protein-protein interactions”. Biochem Mol Biol Educ. 39(4):300-8.
Joanna Miller, D. Scott Witherow, and Susan Carson. (2009) “Assessment of a Novel Laboratory-Intensive Course on RNA Interference.” CBE Life Sci Educ. 8(4):316-25.