Eukaryotic translation elongation factor 1 delta, also known as EEF1D, is a subunit of the elongation factor-1 complex, which is responsible for the enzymatic delivery of aminoacyl tRNAs to the ribosome. This subunit functions as guanine nucleotide exchange factor. It is reported that this subunit interacts with HIV-1 Tat, and thus it represses the translation of host-cell, but not HIV-1, mRNAs.