Involved in protein translation. Together with DOM34, may function in recognizing stalled ribosomes and triggering endonucleolytic cleavage of the mRNA, a mechanism to release non-functional ribosomes and degrade damaged mRNAs. Interacts with DOM34. Present with 2750 molecules/cell in log phase SD medium. Belongs to the TRAFAC class translation factor GTPase superfamily. Classic translation factor GTPase family.