Poster abstracts
Poster number 94 submitted by Alice Duchon
Mechanism of human lysyl-tRNA synthetase/tRNALys preimer recruitment and packaging into HIV-1
Alice Duchon (Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retroviral Research, The Ohio State Un), Nathan Titkemeier (Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retroviral Research, The Ohio State Un), Corine St. Gelais (Department of Veterinary Biosciences, Center for RNA Biology, Center for Retroviral Research, The Ohio State University), Li Wu (Department of Veterinary Biosciences, Center for RNA Biology, Center for Retroviral Research, The Ohio State University), Karin Musier-Forsyth (Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retroviral Research, The Ohio State Un)
Abstract:
The primer for reverse transcription in HIV-1, human tRNALys3, is selectively packaged into virions along with tRNALys1,2. We have previously reported that human lysyl-tRNA synthetase (hLysRS), the only cellular factor known to interact specifically with all three tRNALys isoacceptors, is also packaged into HIV-1 and the presence of both host cell factors is required for optimal viral infectivity. How the hLysRS/tRNALys complex is diverted from its normal cellular location into HIV-1 particles is unknown. hLysRS is normally part of a dynamic mammalian multisynthetase complex (MSC). In recent years, hLysRS has been shown to be mobilized from the MSC and to function in a wide variety of non-translational pathways that involve nuclear localization, membrane binding, and secretion. Here, we show that the expression of hLysRS is unaltered upon HIV-1 infection of HEK293T and CD4+ HuT/CCR5+ T cells, suggesting that the hLysRS species packaged is recruited from an existing pool of LysRS. Immunofluorescence and confocal microscopy imaging reveal that hLysRS is released from the MSC and relocalized to the nucleus upon HIV-1 infection. Our studies also indicate that hLysRS is phosphorylated after HIV-1 infection. This post-translational modification results in release from the MSC and nuclear entry, as pre-treatment of cells with a MEK inhibitor known to block specific hLysRS Ser phosphorylation results in reduced nuclear localization and importantly, reduced HIV-1 infectivity. Taken together, these studies shed light on the mechanism of tRNALys,3 primer recruitment into HIV-1 and suggest a new avenue for targeting a host cell factor that is essential for HIV-1 infection.
Keywords: aminoacyl-tRNA synthetase, HIV, LysRS