Poster abstracts
Poster number 40 submitted by Monica Pillon
CryoEM structure of the SLFN14 endoribonuclease reveals insight into RNA binding and cleavage
Justin Van Riper (Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine), Arleth O. Martinez-Claros (Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine), Lie Wang (Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine), Hannah E. Schneiderman (Department of Structural Biology, University at Buffalo), Sweta Maheshwari (Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine), Monica C. Pillon (Department of Structural Biology, University at Buffalo)
Abstract:
The SLFN14 endoribonuclease is a post-transcriptional regulator that targets the ribosome and its associated RNA substrates for codon-bias translational repression. SLFN14 nuclease activity is linked to antiviral defense and platelet function. Despite its prominent role in gene regulation, the molecular signals regulating SLFN14 substrate recognition and catalytic activation remain unclear. SLFN14 dysregulation is linked to human diseases, including ribosomopathies and inherited thrombocytopenia, thus underscoring the importance of establishing the signals coordinating its RNA processing activity. We reconstitute active full-length human SLFN14 and report a high resolution cryo-EM reconstruction of the SLFN14•RNA complex. The structure reveals a medallion-like architecture that shares structural homology with other SLFN family members. We unveil a C-terminal hydrophobic intermolecular interface that stabilizes the SLFN14 homodimeric RNA cleft. We describe compact RNA binding interfaces within the RNA cleft and highlight the environment of the SLFN14 disease hotspot at the cleft entrance. We show that SLFN14 relies on tRNA modifications for on-target acceptor stem cleavage. Finally, we demonstrate that magnesium-dependent tRNA cleavage requires the SLFN14 E-EhK motif and uncover its unexpected parallel with other virus-activatable nucleases.
Keywords: Ribonuclease, SLFN14, tRNA