SAMHD1 restricts HIV-1 replication in myeloid and quiescent CD4+ Tcells. Here, we show that SAMHD1 restriction activity is regulated by phosphorylation. SAMHD1 interacts with cyclin A2/cdk1 only in cycling cells. Cyclin A2/CDK1 phosphorylates SAMHD1 at the Threonine 592 residue both invitro and invivo. Phosphorylation of SAMHD1 Thr592 correlates with loss of its ability to restrict HIV-1. Indeed, while PMA treatment of proliferating THP1 cells results in reduced Thr592 phosphorylation, activation of resting peripheral blood mononuclear cells (PBMCs) and purifiedquiescent CD4+ Tcells results in increased phosphorylation of SAMHD1 Thr592. Interestingly, we found that treatment of cells by type 1 interferon reduced Thr592 phosphorylation, reinforcing the link between the phosphorylation of SAMHD1 and its antiviral activity. Unlike wild-type SAMHD1, aphosphorylation-defective mutant was able to restrict HIV-1 replication in both PMA-treated anduntreated cells. Our results uncover the phosphorylation of SAMHD1 at Thr592 by cyclin A2/CDK1 as a key regulatory mechanism of its antiviral activity. © 2013 The Authors.
Cribier, A., Descours, B., Valadão, A. L. C., Laguette, N., & Benkirane, M. (2013). Phosphorylation of SAMHD1 by Cyclin A2/CDK1 Regulates Its Restriction Activity toward HIV-1. Cell Reports, 3(4), 1036–1043. https://doi.org/10.1016/j.celrep.2013.03.017