Browsing by Author "DeFoor, Nicole"

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    NAK-associated protein 1/NAP1 activates TBK1 to ensure accurate mitosis and cytokinesis
    Paul, Swagatika; Sarraf, Shireen; Nam, K. H.; Zavar, Leila; DeFoor, Nicole; Biswas, Sahitya; Fritsch, Lauren; Yaron, Tomer; Johnson, Jared; Huntsman, Emily; Cantley, Lewis; Ordureau, Alban; Pickrell, Alicia M. (Rockefeller University Press, 2023-12-07)
    Subcellular location and activation of Tank Binding Kinase 1 (TBK1) govern precise progression through mitosis. Either loss of activated TBK1 or its sequestration from the centrosomes causes errors in mitosis and growth defects. Yet, what regulates its recruitment and activation on the centrosomes is unknown. We identified that NAK-associated protein 1 (NAP1) is essential for mitosis, binding to and activating TBK1, which both localize to centrosomes. Loss of NAP1 causes several mitotic and cytokinetic defects due to inactivation of TBK1. Our quantitative phosphoproteomics identified numerous TBK1 substrates that are not only confined to the centrosomes but are also associated with microtubules. Substrate motifs analysis indicates that TBK1 acts upstream of other essential cell cycle kinases like Aurora and PAK kinases. We also identified NAP1 as a TBK1 substrate phosphorylating NAP1 at S318 to promote its degradation by the ubiquitin proteasomal system. These data uncover an important distinct function for the NAP1-TBK1 complex during cell division.
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    Remdesivir increases mtDNA copy number causing mild alterations to oxidative phosphorylation
    DeFoor, Nicole; Paul, Swagatika; Li, Shuang; Basso, Erwin K. Gudenschwager; Stevenson, Valentina; Browning, Jack L.; Prater, Anna K.; Brindley, Samantha; Tao, Ge; Pickrell, Alicia M. (Springer, 2023-12-01)
    SARS-CoV-2 causes the severe respiratory disease COVID-19. Remdesivir (RDV) was the first fast-tracked FDA approved treatment drug for COVID-19. RDV acts as an antiviral ribonucleoside (adenosine) analogue that becomes active once it accumulates intracellularly. It then diffuses into the host cell and terminates viral RNA transcription. Previous studies have shown that certain nucleoside analogues unintentionally inhibit mitochondrial RNA or DNA polymerases or cause mutational changes to mitochondrial DNA (mtDNA). These past findings on the mitochondrial toxicity of ribonucleoside analogues motivated us to investigate what effects RDV may have on mitochondrial function. Using in vitro and in vivo rodent models treated with RDV, we observed increases in mtDNA copy number in Mv1Lu cells (35.26% increase ± 11.33%) and liver (100.27% increase ± 32.73%) upon treatment. However, these increases only resulted in mild changes to mitochondrial function. Surprisingly, skeletal muscle and heart were extremely resistant to RDV treatment, tissues that have preferentially been affected by other nucleoside analogues. Although our data suggest that RDV does not greatly impact mitochondrial function, these data are insightful for the treatment of RDV for individuals with mitochondrial disease.