Figure 6. ATRA modulates SAMHD1 phosphorylation in a mTOR-dependent manner.

(A–D) MDMs were generated in the presence/absence of ATRA (10 nM) and pretreated or not with INK128 (50 nM), as in Figure 5. Prior to HIV-1 infection, cells were harvested for RT-PCR (A–C) and western blotting investigations (D–F). Shown are mRNA levels of Cyclin D2 (CCND2) (A), CDK1 (B), and SAMHD1 expressions (C), as well as levels of total (molecular weight [MW], 72 kDa) and phosphorylated (MW, 72 kDa) SAMHD1 protein, relative to β-actin (MW, 42 kDa) expression (D) in MDMs from eight different HIV-uninfected donors.

(E and F) Graphs depict total (E) and phosphorylated SAMHD1 protein levels (F) normalized to β-actin expression. Experiments were performed on MDMs from n = 8 HIV-uninfected individuals. Friedman and uncorrected Dunn’s test p values are indicated on the graphs.