Component of the RQC trigger (RQT) complex, a multiprotein complex involved in the ribosome quality control (RQC), a pathway that takes place when a ribosome has stalled during translation. Specifically recognizes and binds RPS20/uS10 ubiquitinated by HEL2, promoting recruitment of the RQT (ribosome quality control trigger) complex on stalled ribosomes, followed by disassembly of stalled ribosomes