GTP-binding protein that couples the Ski complex and exosome%3B putative pseudo-translational GTPase involved in 3'-to-5' mRNA decay pathway%3B interacts with both the cytoplasmic exosome and the Ski complex%3B eRF3-like domain targets nonstop mRNA for degradation%3B null mutants have a superkiller phenotype%3B SKI7 has a paralog%2C HBS1%2C that arose from the whole genome duplication