Knockdown of PPM1A in T cells was reported to result in a decrease in HIV-1 expression [58], a finding that was attributed to the interaction of PPM1A with the pTEFb complex and subsequent effects on RNAP II processivity, which clearly was not the case for macrophages, where PPM1A expression was positively correlated with HIV-1 infection. Here, PPM1A is linked to HIV-1 infection.