Functions as part of the RQC trigger (RQT) complex that activates the ribosome quality control (RQC) pathway, a pathway that degrades nascent peptide chains during problematic translation. Component of the RQT (ribosome quality control trigger) complex, composed of SLH1, CUE3, and RQT4 (PubMed:28757607, PubMed:32203490). Interacts with SLH1 (PubMed:28757607). Interacts with CUE3 (PubMed:28757607, PubMed:28223409). Interacts with HEL2 (PubMed:28757607). Associates with translating ribosomes (PubMed:28757607, PubMed:28223409). Defective activation of the ribosome quality control (RQC) pathway (PubMed:28757607). Mildly defective ribosome stalling induced by RNA arrest sequences (PubMed:28223409). Sensitive to anisomycin (stalls ribosomes in the rotated state) (PubMed:28757607). Present with 1710 molecules/cell in log phase SD medium.