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Updated: May 31, 2026
Analysis of SAMHD1 Restriction by Flow Cytometry in Human Myeloid U937 Cells
Published on: June 13, 2021
SAMHD1: a new insight into HIV-1 restriction in myeloid cells
1Center for Retrovirus Research, Department of Veterinary Bioscience, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210, USA.
Abstract:
Human myeloid-lineage cells are refractory to HIV-1 infection. The Vpx proteins from HIV-2 and sooty mangabey SIV render these cells permissive to HIV-1 infection through proteasomal degradation of a putative restriction factor. Two recent studies discovered the cellular protein SAMHD1 to be this restriction factor, demonstrating that Vpx induces proteasomal degradation of SAMHD1 and enhances HIV-1 infection in myeloid-lineage cells. SAMHD1 functions as a myeloid-cell-specific HIV-1 restriction factor by inhibiting viral DNA synthesis. Here we discuss the implications of these findings in delineating the mechanisms of HIV-1 restriction in myeloid-lineage cells and the potential role of Vpx in lentiviral pathogenesis.
Insights
Human myeloid cells resist HIV-1 infection. Viral Vpx proteins degrade the SAMHD1 restriction factor, enabling HIV-1 entry and replication in these cells, impacting lentiviral pathogenesis.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Human myeloid cells are naturally resistant to HIV-1 infection.
- Viral Vpx proteins from HIV-2 and SIV overcome this resistance.
- This occurs via proteasomal degradation of a cellular restriction factor.
Purpose of the Study:
- To identify the cellular restriction factor targeted by Vpx.
- To elucidate the mechanism of HIV-1 restriction in myeloid cells.
- To explore the role of Vpx in lentiviral pathogenesis.
Main Methods:
- Investigated the interaction between Vpx and cellular proteins.
- Utilized proteasomal degradation assays.
- Assessed HIV-1 infection levels in myeloid cells following SAMHD1 manipulation.
Main Results:
- Identified SAMHD1 as the myeloid-cell-specific HIV-1 restriction factor.
- Demonstrated that Vpx induces the proteasomal degradation of SAMHD1.
- Showed that SAMHD1 degradation enhances HIV-1 infection in myeloid cells by inhibiting viral DNA synthesis.
Conclusions:
- SAMHD1 is a key cellular factor restricting HIV-1 in myeloid cells.
- Vpx-mediated degradation of SAMHD1 is a critical step in overcoming this restriction.
- These findings offer insights into lentiviral pathogenesis and potential therapeutic targets.
