AUTHOR=Nayak Prajna , Kejriwal Aarti , Ratnaparkhi Girish S. TITLE=SUMOylation of Arginyl tRNA Synthetase Modulates the Drosophila Innate Immune Response JOURNAL=Frontiers in Cell and Developmental Biology VOLUME=9 YEAR=2021 URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2021.695630 DOI=10.3389/fcell.2021.695630 ISSN=2296-634X ABSTRACT=

SUMO conjugation of a substrate protein can modify its activity, localization, interaction or function. A large number of SUMO targets in cells have been identified by Proteomics, but biological roles for SUMO conjugation for most targets remains elusive. The multi-aminoacyl tRNA synthetase complex (MARS) is a sensor and regulator of immune signaling. The proteins of this 1.2 MDa complex are targets of SUMO conjugation, in response to infection. Arginyl tRNA Synthetase (RRS), a member of the sub-complex II of MARS, is one such SUMO conjugation target. The sites for SUMO conjugation are Lys 147 and 383. Replacement of these residues by Arg (RRS^K147R,K383R), creates a SUMO conjugation resistant variant (RRS^SCR). Transgenic Drosophila lines for RRS^WT and RRS^SCR were generated by expressing these variants in a RRS loss of function (lof) animal, using the UAS-Gal4 system. The RRS-lof line was itself generated using CRISPR/Cas9 genome editing. Expression of both RRS^WT and RRS^SCR rescue the RRS-lof lethality. Adult animals expressing RRS^WT and RRS^SCR are compared and contrasted for their response to bacterial infection by gram positive M. luteus and gram negative Ecc15. We find that RRS^SCR, when compared to RRS^WT, shows modulation of the transcriptional response, as measured by quantitative 3′ mRNA sequencing. Our study uncovers a possible non-canonical role for SUMOylation of RRS, a member of the MARS complex, in host-defense.