Subunit of ribosome-associated quality control trigger complex (RQT); contains ATPase activity required for subunit dissociation of non-functional 80S ribosomes containing polyubiquitinated Rps3p, leading to Xrn1-dependent degradation of the non-functional 18S rRNA; blocks translation of non-poly(A) mRNAs; required to repress the propagation of dsRNA viruses; RNA helicase-family protein related to Ski2p; human homolog is ASCC3