Identification and characterization of Arginyl-tRNA synthetase translation-independent functions

• Applicant: Dr. Haissi Cui
• Subject Area: Cell Biology ; Biochemistry
• Term: from 2016 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 327097878

Aminoacyl-tRNA Synthetases are ancient enzymes, which catalyze the correct charging of tRNAs with the respective amino acid. As such, they are the main interpreter of the genetic code and essential for mRNA translation. In addition, aminoacyl-tRNA Synthetases are regulators of cell signal transduction and gene expression, which is in part mediated by their recently identified splice isoforms. So far, non-translational functions of Arginyl-tRNA Synthetase (ArgRS) remain unstudied despite the regulatory role of arginine, the presence of ArgRS in the nucleus, and altered stem cell signaling and proliferation upon stimulation with ArgRS splice isoform ArgRS-N2. In the project suggested here, signaling of ArgRS and its impact on cell proliferation, differentiation, and signal transduction will be investigated. Identification of receptors and involved signaling pathways can reveal additional biological roles of ArgRS. Endogenous overexpression and exogenous stimulation with other splice isoforms and full-length protein combined with microarray analysis may be used to assess if signaling is limited to ArgRS-N2. Co-immunoprecipitation followed by mass spectrometrical analysis will allow identification of interaction partners that regulate ArgRS-derived effects. These results can be verified using co-localization in fluorescence microscopy, which also displays ArgRS dynamics with respect to cellular localization. If catalytically active ArgRS regulates cell signaling, arginine analogues can be used to stimulate or inhibit ArgRS effects. In summary, studying ArgRS signaling and the underlying mechanisms could lead to the discovery of previously unknown functions of ArgRS, a protein with undisputable importance for the cell.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Paul Schimmel