GuanQun ‘Leo’ Liu, Ph.D.
Cleveland Clinic Florida Research and Innovation Center
Port St. Lucie, USA
Dr. GuanQun ‘Leo’ Liu is a postdoctoral fellow in the laboratory of Prof. Michaela Gack at the Cleveland Clinic Florida Research and Innovation Center. He was trained as a molecular virologist with extensive research experience in innate immune sensing of viral infections and type I interferon-mediated antiviral immunity. During his Ph.D. training at the University of Saskatchewan in Canada, he identified and characterized a series of viral RNA ligands produced from influenza A virus infection that are key to the activation of the innate immune RNA sensor, retinoic acid-inducible gene I (RIG-I). He also identified nuclear-resident RIG-I that senses nuclear-replicating viruses and induces antiviral cytokine responses, which provides the first evidence of a non-self RNA sensing paradigm in the nucleus, a previously unrecognized subcellular milieu for RIG-I-like receptor (RLR) sensing. Leo’s postdoctoral training with Dr. Gack has extended his research scope to the regulation of antiviral innate immunity with an emphasis on the post-translational control of RLR activation. He recently identified ISGylation as an essential post-translational modification responsible for the activation of the RNA sensor melanoma differentiation-associated protein 5 (MDA5), and unraveled how SARS coronaviruses, by antagonizing this mechanism, evade the MDA5-mediated antiviral cytokine response. As an enthusiastic and highly motivated researcher driven by scientific unknowns, his long-term research goal is to develop a comprehensive understanding of the mechanistic relationships between cellular compartmentalization and the regulation of innate immune sensing and cytokine responses during viral infections and in autoimmune diseases. Leo’s work has been recognized in the 2018 Young Innovators series by the University of Saskatchewan Research Profile and Impact office in partnership with the Saskatoon StarPhoenix.