Poster abstracts
Poster number 14 submitted by Morgan Bauer
Enzymatic Characterization of Full-length Glutamyl-Prolyl-tRNA Synthetase (EPRS) and Disease-associated Mutants
Morgan Bauer (Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, OH, USA. *Bauer.715buckeyemail.osu.edu ), Brianna Young (Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, OH, USA.), Sabat Gonzalez-Serrano (William G. Lowrie Department of Chemical and Biomolecular Engineering, Ohio State University, Columbus, OH, USA ), David Wood (William G. Lowrie Department of Chemical and Biomolecular Engineering, Ohio State University, Columbus, OH, USA ), Karin Musier-Forsyth (Department of Chemistry and Biochemistry, Center for RNA Biology, Ohio State University, Columbus, OH, USA. )
Abstract:
Glutamyl-prolyl-tRNA synthetase (EPRS) catalyzes the attachment of proline and glutamic acid onto their respective tRNAs. Out of all the aminoacyl-tRNA synthetases, EPRS is the only bifunctional synthetase, with two catalytic cores connected by a linker domain. EPRS resulted from a fusion event between stand-alone glutamyl- and prolyl-tRNA synthetases (ERS and PRS, respectively) during evolution around the creation of metazoans, and remained encoded in all animals. Fox and co-workers proposed that this fused protein is metabolically advantageous for organisms by keeping the proline and glutamic acid pool at cellular homeostasis. Whether EPRS catalytic activity differs relative to the stand-alone synthetases is unknown. Previous work on EPRS has shown that it performs many non-canonical functions, such as translational repression of inflammatory mRNAs, increasing the intake of long-chain fatty acids and repressing viral replication. However, the full-length enzyme has never been characterized in vitro. We successfully purified full-length EPRS from mammalian cells for the first time and characterized its enzymatic activity. Compared to ERS and PRS domains alone, the fused catalytic domains of EPRS are more efficient at aminoacylating tRNA. These preliminary findings reveal a new advantage of ERS and PRS fusion. Mutations in EPRS are linked to patients with hypomyelinating leukodystrophy and other neurological disorders. Novel bi-allelic point mutations from five affected individuals have recently been identified. Ongoing studies are aimed at characterizing disease-associated mutations in both full-length EPRS and separate ERS and PRS domains. Our long-term goal is to identify the disease mechanisms underlying EPRS-related disorders and uncover future therapeutic strategies.
Keywords: tRNA