PEBP1 interacts and inhibits the activity of Raf1 and IKK kinases. This blocks the phosphorylation of downstream proteins ERK1, IKK and IκBα, resulting in the sequestration of p65/p50 heterodimer in the cytoplasm, thereby silencing HIV-1 transcription. When PEBP1 is knocked out, Raf1 and IKK signaling pathways are activated to phosphorylate IκBα, thereby releasing p65/p50 heterodimer to translocate into the nucleus to drive HIV-1 transcription. 