SAMHD1 phosphorylation and cytoplasmic relocalization after human cytomegalovirus infection limits its antiviral activity

PLoS Pathog. 2020 Sep 28;16(9):e1008855. doi: 10.1371/journal.ppat.1008855. eCollection 2020 Sep.

Abstract

SAMHD1 is a host restriction factor that functions to restrict both retroviruses and DNA viruses, based on its nuclear deoxynucleotide triphosphate (dNTP) hydrolase activity that limits availability of intracellular dNTP pools. In the present study, we demonstrate that SAMHD1 expression was increased following human cytomegalovirus (HCMV) infection, with only a modest effect on infectious virus production. SAMHD1 was rapidly phosphorylated at residue T592 after infection by cellular cyclin-dependent kinases, especially Cdk2, and by the viral kinase pUL97, resulting in a significant fraction of phosho-SAMHD1 being relocalized to the cytoplasm of infected fibroblasts, in association with viral particles and dense bodies. Thus, our findings indicate that HCMV-dependent SAMHD1 cytoplasmic delocalization and inactivation may represent a potential novel mechanism of HCMV evasion from host antiviral restriction activities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiviral Agents / pharmacology
  • Cyclin-Dependent Kinases / metabolism
  • Cytomegalovirus / genetics
  • Cytomegalovirus / pathogenicity*
  • Cytomegalovirus Infections / virology*
  • Cytoplasm / metabolism
  • Cytoplasm / virology
  • Herpesviridae Infections / metabolism*
  • Humans
  • Monomeric GTP-Binding Proteins / metabolism
  • Phosphorylation
  • SAM Domain and HD Domain-Containing Protein 1 / genetics*
  • Virus Replication / drug effects

Substances

  • Antiviral Agents
  • Cyclin-Dependent Kinases
  • SAM Domain and HD Domain-Containing Protein 1
  • SAMHD1 protein, human
  • Monomeric GTP-Binding Proteins

Grants and funding

This work was supported by grants from the Italian Ministry of University and Research (PRIN 2015-W729WH to CC; 2015-RMNSTA to VDO). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.