The missing link: allostery and catalysis in the anti-viral protein SAMHD1 DOI Creative Commons
E.R. Morris, Ian A. Taylor

Biochemical Society Transactions, Journal Year: 2019, Volume and Issue: 47(4), P. 1013 - 1027

Published: July 11, 2019

Abstract Vertebrate protein SAMHD1 (sterile-α-motif and HD domain containing 1) regulates the cellular dNTP (2′-deoxynucleoside-5′-triphosphate) pool by catalysing hydrolysis of into 2′-deoxynucleoside triphosphate products. As an important regulator cell proliferation a key player in homeostasis, mutations to are implicated hypermutated cancers, germline associated with Chronic Lymphocytic Leukaemia inflammatory disorder Aicardi–Goutières Syndrome. By limiting supply dNTPs for viral DNA synthesis, also restricts replication several retroviruses, such as HIV-1, some viruses dendritic myeloid lineage cells resting T-cells. activity is regulated throughout cycle, both at level expression post-translationally, through phosphorylation. In addition, allosteric regulation further fine-tunes catalytic SAMHD1, nucleotide-activated homotetramer catalytically active form protein. cells, GTP dATP likely physiological activators two adjacent sites, AL1 (GTP) AL2 (dATP), that bridge monomer–monomer interfaces stabilise homotetramer. This review summarises extensive X-ray crystallographic, biophysical molecular dynamics experiments have elucidated features SAMHD1. We present comprehensive mechanism detailing structural components coupling between nucleotide-induced tetramerization catalysis

Language: Английский

SAMHD1 shapes deoxynucleotide triphosphate homeostasis by interconnecting the depletion and biosynthesis of different dNTPs DOI Creative Commons
Claudia McCown, Corey H. Yu, Dmitri N. Ivanov

et al.

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 17, 2025

SAMHD1 is a dNTPase that impedes replication of HIV-1 in myeloid cells and resting T lymphocytes. Here we elucidate the substrate activation mechanism SAMHD1, which involves dNTP binding at allosteric sites transient tetramerization. Our findings reveal tetramerization alone insufficient to promote hydrolysis; instead, requires an inactive tetrameric intermediate with partially occupied sites. The equilibrium between active states regulates activity, driven by dissociation additional ligands preassembled tetramer. Furthermore, catalytic efficiency, but not specificity, modulated identity dNTPs occupying We show how this regulation shapes deoxynucleotide homeostasis balancing production SAMHD1-catalyzed depletion. Notably, exhibits distinct functionality, term facilitated depletion, whereby increased biosynthesis certain enhances depletion others. regulatory relationship different sheds light on emerging role biology implications for HIV/AIDS, innate antiviral immunity, cell disorders, telomere maintenance therapeutic efficacy nucleoside analogs.

Language: Английский

Citations

3
Protein phosphatases in the regulation of mitosis DOI Creative Commons
Jakob Nilsson

The Journal of Cell Biology, Journal Year: 2018, Volume and Issue: 218(2), P. 395 - 409

Published: Nov. 16, 2018

The accurate segregation of genetic material to daughter cells during mitosis depends on the precise coordination and regulation hundreds proteins by dynamic phosphorylation. Mitotic kinases are major regulators protein function, but equally important phosphatases that balance their actions, coordinated activity being essential for chromosome segregation. Phosphoprotein (PPPs) dephosphorylate phosphoserine phosphothreonine residues increasingly understood as mitosis. In contrast kinases, lack a pronounced peptide-binding cleft catalytic subunit PPPs suggests these enzymes unlikely be specific. However, recent exciting insights into how mitotic recognize specific substrates have revealed they kinases. Furthermore, activities tightly controlled at many levels ensure active only proper time place. Here, I will discuss substrate selection focusing mainly animal explore actions control mitosis, well unanswered questions.

Language: Английский

Citations

101
Protein phosphatase 2A as a therapeutic target in inflammation and neurodegeneration DOI Creative Commons
Andrew R. Clark, Michael Ohlmeyer

Pharmacology & Therapeutics, Journal Year: 2019, Volume and Issue: 201, P. 181 - 201

Published: June 1, 2019

Protein phosphatase 2A (PP2A) is a highly complex heterotrimeric enzyme that catalyzes the selective removal of phosphate groups from protein serine and threonine residues. Emerging evidence suggests it functions as tumor suppressor by constraining phosphorylation-dependent signalling pathways regulate cellular transformation metastasis. Therefore, PP2A-activating drugs (PADs) are being actively sought investigated potential novel anti-cancer treatments. Here we explore concept PP2A also constrains inflammatory responses through its inhibitory effects on various pathways, suggesting PADs may be effective in treatment inflammation-mediated pathologies.

Language: Английский

Citations

84
SAMHD1 Functions and Human Diseases DOI Creative Commons
Si’Ana A. Coggins, Bijan Mahboubi, Raymond F. Schinazi

et al.

Viruses, Journal Year: 2020, Volume and Issue: 12(4), P. 382 - 382

Published: March 31, 2020

Deoxynucleoside triphosphate (dNTP) molecules are essential for the replication and maintenance of genomic information in both cells a variety viral pathogens. While process dNTP biosynthesis by cellular enzymes, such as ribonucleotide reductase (RNR) thymidine kinase (TK), has been extensively investigated, negative regulatory mechanism pools was recently found to involve sterile alpha motif (SAM) domain histidine-aspartate (HD) domain-containing protein 1, SAMHD1. When active, triphosphohydrolase activity SAMHD1 degrades dNTPs into their 2'-deoxynucleoside (dN) subparts, steadily depleting intercellular pools. The differential expression levels activation states various cell types contributes unique that either aid (i.e., dividing T cells) or restrict nondividing macrophages) consumes dNTPs. Genetic mutations induce rare inflammatory encephalopathy called Aicardi-Goutières syndrome (AGS), which phenotypically resembles infection. Recent publications have identified diverse roles double-stranded break repair, genome stability, stress response through interferon signaling. Finally, series were also reported cancer while why is mutated these remains investigated. Here, we reviewed studies begun illuminating highly virology, immunology, biology.

Language: Английский

Citations

82
SAMHD1 Modulates Early Steps during Human Cytomegalovirus Infection by Limiting NF-κB Activation DOI Creative Commons
Eui Tae Kim,

Kathryn L. Roche,

Katarzyna Kulej

et al.

Cell Reports, Journal Year: 2019, Volume and Issue: 28(2), P. 434 - 448.e6

Published: July 1, 2019

Highlights•HCMV infection induces SAMHD1 expression and phosphorylation•SAMHD1 restricts HCMV gene before virus replication•SAMHD1 deficiency limits entry into the quiescent stage of infection•HCMV restriction by is mediated limiting NF-κB activationSummaryCellular inhibits replication many viruses intracellular deoxynucleoside triphosphate (dNTP) pools. We investigate influence on human cytomegalovirus (HCMV). During infection, we observe induction, accompanied phosphorylation via viral kinase UL97. depletion increases in permissive fibroblasts conditionally myeloid cells. show this due to enhanced from major immediate-early (MIE) promoter independent dNTP levels. suppresses innate immune responses inhibiting nuclear factor κB (NF-κB) activation. that regulates MIE through Chromatin immunoprecipitation reveals increased RELA RNA polymerase II absence SAMHD1. Our studies reveal a mechanism how activates an pathway paradoxically results transcriptional activation promoter.Graphical abstract

Language: Английский

Citations

57
Spatial resolution of HIV-1 post-entry steps in resting CD4 T cells DOI Creative Commons
Swetha Ananth,

Ina Ambiel,

Sandra Schifferdecker

et al.

Cell Reports, Journal Year: 2024, Volume and Issue: 43(3), P. 113941 - 113941

Published: March 1, 2024

Resting CD4 T cells resist productive HIV-1 infection. The HIV-2/simian immunodeficiency virus protein viral accessory X (Vpx) renders these permissive to infection, presumably by alleviating blocks at cytoplasmic reverse transcription and subsequent nuclear import of reverse-transcription/pre-integration complexes (RTC/PICs). Here, spatial analyses using quantitative imaging techniques reveal that capsids containing RTC/PICs are readily imported into the nucleus, recruit host dependency factor CPSF6, translocate speckles in resting cells. Reverse transcription, however, remains incomplete, impeding proviral integration gene expression. Vpx or pharmacological inhibition deoxynucleotide triphosphohydrolase (dNTPase) activity restriction SAM domain HD domain-containing 1 (SAMHD1) increases levels reverse-transcribed cDNA facilitates integration. Nuclear intranuclear transport therefore do not pose important cells, limitation SAMHD1's dNTPase constitutes main pre-integration block

Language: Английский

Citations

7
SAMHD1 and the innate immune response to cytosolic DNA during DNA replication DOI
Flavie Coquel, Christoph Neumayer, Yea‐Lih Lin

et al.

Current Opinion in Immunology, Journal Year: 2018, Volume and Issue: 56, P. 24 - 30

Published: Oct. 4, 2018

Language: Английский

Citations

51
Nucleic acid binding by SAMHD1 contributes to the antiretroviral activity and is enhanced by the GpsN modification DOI Creative Commons
Corey H. Yu, Akash Bhattacharya, Mirjana Persaud

et al.

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Feb. 2, 2021

Abstract SAMHD1 impedes infection of myeloid cells and resting T lymphocytes by retroviruses, the enzymatic activity protein—dephosphorylation deoxynucleotide triphosphates (dNTPs)—implicates dNTP depletion in innate antiviral immunity. Here we show that allosteric binding sites enzyme are plastic can accommodate oligonucleotides place activators, GTP dNTP. displays a preference for containing phosphorothioate bonds Rp configuration located 3’ to G nucleotides (GpsN), modification pattern occurs mechanism defense prokaryotes. In presence dNTPs, GpsN-containing promotes formation distinct tetramer with mixed occupancy sites. Mutations impair mixed-occupancy complex abolish antiretroviral SAMHD1, but not its ability deplete dNTPs. The findings link nucleic acid shed light on immunomodulatory effects synthetic phosphorothioated raise questions about role phosphorothioation human

Language: Английский

Citations

37
Protein Phosphatase 2A (PP2A) mutations in brain function, development, and neurologic disease DOI
Iris Verbinnen, Pieter Vaneynde,

Sara Reynhout

et al.

Biochemical Society Transactions, Journal Year: 2021, Volume and Issue: 49(4), P. 1567 - 1588

Published: July 9, 2021

By removing Ser/Thr-specific phosphorylations in a multitude of protein substrates diverse tissues, Protein Phosphatase type 2A (PP2A) enzymes play essential regulatory roles cellular signalling and physiology, including brain function development. Here, we review current knowledge on PP2A gene mutations causally involved neurodevelopmental disorders intellectual disability, focusing PPP2CA, PPP2R1A PPP2R5D. We provide insights into the impact these structure, substrate specificity potential neurobiology

Language: Английский

Citations

35
30 years of nanobodies – an ongoing success story of small binders in biological research DOI Creative Commons
Desiree I. Frecot,

Theresa Froehlich,

Ulrich Rothbauer

et al.

Journal of Cell Science, Journal Year: 2023, Volume and Issue: 136(21)

Published: Nov. 1, 2023

ABSTRACT A milestone in the field of recombinant binding molecules was achieved 30 years ago with discovery single-domain antibodies from which antigen-binding variable domains, better known as nanobodies (Nbs), can be derived. Being only one tenth size conventional antibodies, Nbs feature high affinity and specificity, while being highly stable soluble. In addition, they display accessibility to cryptic sites, low off-target accumulation deep tissue penetration. Efficient selection methods, such (semi-)synthetic/naïve or immunized cDNA libraries technologies, have facilitated isolation against diverse targets, their single-gene format enables easy functionalization high-yield production. This Review highlights recent advances Nb applications various areas biological research, including structural biology, proteomics high-resolution vivo imaging. we provide insights into intracellular Nbs, live-cell imaging, biosensors targeted protein degradation.

Language: Английский

Citations

14