Helicase component of the SKI complex, a multiprotein complex that assists the RNA-degrading exosome during the mRNA decay and quality-control pathways (PubMed:16024656, PubMed:32006463, PubMed:35120588). The SKI complex catalyzes mRNA extraction from 80S ribosomal complexes in the 3'-5' direction and channels mRNA to the cytosolic exosome for degradation (PubMed:32006463, PubMed:35120588). SKI-mediated extraction of mRNA from stalled ribosomes allow binding of the Pelota-HBS1L complex and subsequent ribosome disassembly by ABCE1 for ribosome recycling (PubMed:32006463). In the nucleus, the SKI complex associates with transcriptionally active genes in a manner dependent on PAF1 complex (PAF1C) (PubMed:16024656). May play a role in the non-stop mRNA decay pathway (NSD), which specifically targets and degrades mRNAs that lack a proper stop codon (PubMed:40441874). {ECO:0000269|PubMed:16024656, ECO:0000269|PubMed:32006463, ECO:0000269|PubMed:35120588, ECO:0000269|PubMed:40441874}. This is the function of Ensembl gene identifier ENSG00000204351 (SKIC2, SKI2 subunit of superkiller complex).