Structures and Activities of the Elongator Complex and Its Cofactors

Elongator is a highly conserved eukaryotic protein complex consisting of two sets of six Elp proteins, while homologues of its catalytic subunit Elp3 are found in all the kingdoms of life. Although it was originally described as a transcription elongation factor, cumulating evidence suggests that its primary function is catalyzing tRNA modifications. In humans, defects in Elongator subunits are associated with neurological disorders and cancer. Although further studies are still required, a clearer picture of the molecular mechanism of action of Elongator and its cofactors has started to emerge within recent years that have witnessed significant development in the field. In this review we summarize recent Elongator-related findings provided largely by crystal structures of several subunits of the complex, the electron microscopy structure of the entire yeast holoenzyme, as well as the structure of the Elongator cofactor complex Kti11/Kti13.