Single-Stranded Nucleic Acids Bind to the Tetramer Interface of SAMHD1 and Prevent Formation of the Catalytic Homotetramer

Biochemistry, Год журнала: 2016, Номер 55(44), С. 6087 - 6099

Опубликована: Окт. 24, 2016

Sterile alpha motif and HD domain protein 1 (SAMHD1) is a unique enzyme that plays important roles in nucleic acid metabolism, viral restriction, the pathogenesis of autoimmune diseases cancer. Although much attention has been focused on its dNTP triphosphohydrolase activity restriction disease, SAMHD1 also binds to single-stranded RNA DNA. Here we utilize UV cross-linking method using 5-bromodeoxyuridine-substituted oligonucleotides coupled with high-resolution mass spectrometry identify binding site for acids (ssNAs) SAMHD1. Mapping cross-linked amino surface existing crystal structures demonstrated ssNA lies largely along dimer-dimer interface, sterically blocking formation homotetramer required dNTPase activity. Surprisingly, disordered C-terminus (residues 583-626) was implicated binding. An interaction between this region confirmed studies purified 583-626 peptide. Despite recent report possesses polyribonucleotide phosphorylase activity, did not detect any such presence inorganic phosphate, indicating unrelated proposed These data suggest an antagonistic regulatory mechanism which mutually exclusive oligomeric state requirements hydrolase modulate these two functions within cell.

Язык: Английский

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Inhibition of hepatitis B virus replication by a dNTPase-dependent function of the host restriction factor SAMHD1

Virology, Год журнала: 2016, Номер 495, С. 71 - 78

Опубликована: Май 11, 2016

Язык: Английский

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The SAMHD1 dNTP Triphosphohydrolase Is Controlled by a Redox Switch

Antioxidants and Redox Signaling, Год журнала: 2017, Номер 27(16), С. 1317 - 1331

Опубликована: Фев. 24, 2017

Proliferative signaling involves reversible posttranslational oxidation of proteins. However, relatively few molecular targets these modifications have been identified. We investigate the role protein in regulation SAMHD1 catalysis.Here we report that is a major target for redox nucleotide metabolism and cell cycle control. triphosphate hydrolase, whose function deoxynucleotide pools. demonstrate state regulates its catalytic activity. identified three cysteine residues constitute an intrachain disulfide bond "redox switch" reversibly inhibits tetramerization catalysis. show proliferative signals lead to cells oxidized localized outside nucleus. Innovation Conclusions: activity regulated by oxidation. These data identify previously unknown mechanism SAMHD1. Antioxid. Redox Signal. 27, 1317-1331.

Язык: Английский

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TLR4-Mediated Pathway Triggers Interferon-Independent G0 Arrest and Antiviral SAMHD1 Activity in Macrophages

Cell Reports, Год журнала: 2020, Номер 30(12), С. 3972 - 3980.e5

Опубликована: Март 1, 2020

Macrophages exist predominantly in two distinct states, G0 and a G1-like state that is accompanied by phosphorylation of SAMHD1 at T592. Here, we demonstrate Toll-like receptor 4 (TLR4) activation can potently induce arrest antiretroviral activity an interferon (IFN)-independent pathway. This pathway requires TLR4 engagement with TRIF, but not involvement TBK1 or IRF3. Exclusive Myd88 activators are unable to trigger dephosphorylation, demonstrating this also Myd88/nuclear factor κB (NF-κB) independent. The p21 upregulation CDK1 depletion, consistent the observed dephosphorylation Furthermore, show knockdown TLR4-activated blocks HIV-1 infection macrophages specifically via SAMHD1. Together, these data mobilize intrinsic cell anti-viral activating prior IFN secretion, thereby highlighting importance cell-cycle regulation as response pathogen-associated danger signals macrophages.

Язык: Английский

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Crystal structures of SAMHD1 inhibitor complexes reveal the mechanism of water-mediated dNTP hydrolysis

Nature Communications, Год журнала: 2020, Номер 11(1)

Опубликована: Июнь 23, 2020

Abstract SAMHD1 regulates cellular 2′-deoxynucleoside-5′-triphosphate (dNTP) homeostasis by catalysing the hydrolysis of dNTPs into 2′-deoxynucleosides and triphosphate. In CD4 + myeloid lineage resting T-cells, blocks HIV-1 other viral infections depletion dNTP pool to a level that cannot support replication. mutations are associated with autoimmune disease Aicardi–Goutières syndrome hypermutated cancers. Furthermore, sensitises cancer cells nucleoside-analogue anti-cancer therapies is linked DNA repair suppression interferon response cytosolic nucleic acids. Nevertheless, despite its requirement in these processes, fundamental mechanism SAMHD1-catalysed remained unknown. Here, we present structural enzymological data showing utilises an active site, bi-metallic iron-magnesium centre positions hydroxide nucleophile in-line P α -O 5′ bond catalyse phosphoester hydrolysis. This precise molecular for catalysis, reveals how down-regulates modulates efficacy nucleoside-based anti-viral therapies.

Язык: Английский

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