Insights into the Structure, Pharmacology, and Evolution of the Glycine Transporter 2
The balance between neuronal excitation and inhibition in the central nervous system is vital for survival. Overexcitation can be toxic and lead to certain manias or even death. On the other hand, extremely low levels of inhibition cause hyperekplexia, pain, and even forms of autism. Neuronal inhibition is, for the most part, achieved by two neurotransmitters, GABA and glycine. Levels of both neurotransmitters in the synaptic cleft are meticulously regulated by the GABA and glycine transporters, respectively, which belong to the solute carrier 6 (SLC6) family of neurotransmitter transporters and share structural similarities with other family members. In Chapter 1, we aimed to understand the function of the amino terminus of glycine transporter 2 (GlyT2) by identifying possible interacting partners using biochemical techniques such as immunoprecipitation and Western blots. However, we were unsuccessful at identifying an interacting protein at the N-terminus of GlyT2. We believe that the high complexity of the N-terminal sequence and the degree of disorder in the structure resulted in transient and weak interactions between N-terminus and interacting proteins. In Chapter 2 of this dissertation, we aimed to develop specific inhibitors of GlyT2. Using molecular dynamics simulations and docking experiments we predicted four compounds that could inhibit GlyT2 activity, and by using glycine uptake assays we demonstrated the lack of activity of these inhibitors in GlyT1. As a result, we showed the specific inhibition of GlyT2 over GlyT1 in-vitro. In 5, we aimed to further elucidate the evolution of GlyT2 through the use of in-silico and biochemical functional assays to characterize a gene (CG5549) in Drosophila melanogaster that resembles a glycine transporter. However, our results indicated that the lack of efficient glycine transport in CG5549 expressed in a mammalian cell line provides enough evidence to prove that this gene is not a glycine transporter.
Lopez, Ashley Bryan, "Insights into the Structure, Pharmacology, and Evolution of the Glycine Transporter 2" (2020). ETD Collection for University of Texas, El Paso. AAI27999226.