Updated project metadata. During the course of HIV infection, host ubiquitination pathways are both attempting to fight off infection and are being hijacked by the virus in an attempt to optimally infect our cells. In order to more fully understand the role ubiquitination plays in HIV infection, we first defined the set of ubiquitin ligases expressed in primary CD4+ T cells using mass spectrometry. Out of the approximately 380 total ligases, we identified 116 that were expressed, and proceeded to delete them individually in primary CD4+ cells using an arrayed CRISPR/Cas9 approach.