Dual E3 ligase function of TRIM25 in modulating innate immunity - Project summary/abstract Innate immunity is crucial for human health and is primarily regulated by post-translational modifications, such as ubiquitin and ubiquitin-like (ubl) modifiers. Specifically, Tripartite motif-containing protein 25 (TRIM25), is an E3 ligase that enzymatically modifies substrates with ubiquitin and the ubl protein ISG15 and participates in modulating innate immunity through the immunoreceptors Retinoic acid-inducible gene I-like receptors (RLRs). Despite a general understanding of the role TRIM25 plays in the ubiquitination of RIG-I, little is known about the role TRIM25 plays in ISGylation of RLRs and how TRIM25 selects between either process. Further, a new viral mode of antagonism of TRIM25 by the Human Papilloma Virus have been discovered but have not been defined at the molecular level. In this proposal, In the K99 phase of this award (Aim 1), I will investigate the mechanism of the viral E6 antagonism of TRIM25 and how this inhibition effects the dual functions of TRIM25 to ubiquitinate and ISGylate RLRs. In the R00 phase of this award (Aim 2, I will dissect the functional selectivity of TRIM25 and the effects this has on substrate modification. This research will provide me with training in yeast display systems, directed evolution and biochemistry and research on TRIM25 bifunctionality will be carried over to my own lab. This award will enable me to take advantage of protein engineering and immunology expertise via my advisory committee (Dr. Binning and Dr. Pilon-Thomas), as well as career development opportunities at the Moffitt Cancer Center. I will also bolster my previous experience in diversity, equity and inclusion (DEI) advocacy with new training to best position myself to further DEI efforts throughout my institution and community. I will attend conferences and participate in Moffitt-sponsored and MOSAIC UE5 initiatives focused on lab management and leadership. This will aid me transition to an independent scientist specializing in Ubiquitin biology and innate immunity, which is a rapidly growing and important area of scientific research.
