UBQLN2, also known as Ubiquilin-2, is a protein involved in the ubiquitin–proteasome system (UPS), a crucial pathway for protein degradation within cells. It contains ubiquitin-like (UBL) and ubiquitin-associated (UBA) domains that facilitate interactions with ubiquitinated proteins and components of the proteasome. UBQLN2 acts as a shuttle factor, transporting ubiquitinated proteins to the proteasome for degradation and aiding in protein quality control.