Instead, the ability of SAMHD1 to block HIV-1 infection appears to be regulated by the phosphorylation status of the threonine residue at position 592 (T592) in SAMHD1 (13, 15, 17), with T592 phosphorylation inhibiting the ability of SAMHD1 to block HIV-1 infection (13, 15, 17). Here, SAMHD1 is linked to HIV-1 infection.