Effects of T592 phosphomimetic mutations on tetramer stability and dNTPase activity of SAMHD1 can not explain the retroviral restriction defect

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dc.contributor.authorBhattacharya, Akash
dc.contributor.authorWang, Zhonghua
dc.contributor.authorWhite, Tommy
dc.contributor.authorBuffone, Cindy
dc.contributor.authorNguyen, Laura A.
dc.contributor.authorShepard, Caitlin N.
dc.contributor.authorKim, Baek
dc.contributor.authorDemeler, Borries
dc.contributor.authorDiaz-Griffero, Felipe
dc.contributor.authorIvanov, Dmitri N.
dc.date.accessioned2021-10-13T18:28:06Z
dc.date.available2021-10-13T18:28:06Z
dc.date.issued2016
dc.descriptionOpen access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) appliesen_US
dc.description.abstractSAMHD1, a dNTP triphosphohydrolase, contributes to interferon signaling and restriction of retroviral replication. SAMHD1-mediated retroviral restriction is thought to result from the depletion of cellular dNTP pools, but it remains controversial whether the dNTPase activity of SAMHD1 is sufficient for restriction. The restriction ability of SAMHD1 is regulated in cells by phosphorylation on T592. Phosphomimetic mutations of T592 are not restriction competent, but appear intact in their ability to deplete cellular dNTPs. Here we use analytical ultracentrifugation, fluorescence polarization and NMR-based enzymatic assays to investigate the impact of phosphomimetic mutations on SAMHD1 tetramerization and dNTPase activity in vitro. We find that phosphomimetic mutations affect kinetics of tetramer assembly and disassembly, but their effects on tetramerization equilibrium and dNTPase activity are insignificant. In contrast, the Y146S/Y154S dimerization-defective mutant displays a severe dNTPase defect in vitro, but is indistinguishable from WT in its ability to deplete cellular dNTP pools and to restrict HIV replication. Our data suggest that the effect of T592 phosphorylation on SAMHD1 tetramerization is not likely to explain the retroviral restriction defect and we hypothesize that enzymatic activity of SAMHD1 is subject to additional cellular regulatory mechanisms that have not yet been recapitulated in vitro.en_US
dc.description.peer-reviewYesen_US
dc.identifier.citationBhattacharya, A., Wang, Z., White, T., Buffone, C., Nguyen, L. A., Shepard, C. N., Kim, B., Demeler, B., Diaz-Griffero, F., & Ivanov, D. N. (2016). Effects of T592 phosphomimetric mutations on tetramer stability and dNTPase activity of SAMHD1 can not explain the retroviral restriction defect. Scientific Reports, 6, Article 31353. https://doi.org/10.1038/srep31353en_US
dc.identifier.urihttps://hdl.handle.net/10133/6058
dc.language.isoen_USen_US
dc.publisherNature Publishingen_US
dc.publisher.departmentDepartment of Chemistry and Biochemistryen_US
dc.publisher.facultyArts and Scienceen_US
dc.publisher.institutionUniversity of Texas Health Science Center at San Antonioen_US
dc.publisher.institutionAlbert Einstein College of Medicineen_US
dc.publisher.institutionEmory School of Medicineen_US
dc.publisher.institutionKyunghee Universityen_US
dc.publisher.institutionUniversity of Lethbridgeen_US
dc.publisher.urlhttps://doi.org/10.1038/srep31353en_US
dc.subjectEnzyme mechanismsen_US
dc.subjectPhosphomimetic mutations
dc.subjectSAMHD1
dc.subjectTetramer stability
dc.subjectRetroviral
dc.subject.lcshHIV infections
dc.titleEffects of T592 phosphomimetic mutations on tetramer stability and dNTPase activity of SAMHD1 can not explain the retroviral restriction defecten_US
dc.typeArticleen_US
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