Slippery sequences stall the 26S proteasome at multiple points along the translocation pathway.

In eukaryotes, the ubiquitin-proteasome system is responsible for intracellular protein degradation. Proteins tagged with ubiquitin are recognized by ubiquitin receptors on the 19S regulatory particle (RP) of the 26S proteasome, unfolded, routed through the translocation channel of the RP, and are then degraded in the 20S core particle (CP). Aromatic paddles on the pore-1 loops of the RP's Rpt subunits grip the substrate and pull folded domains into the channel, thereby unfolding them.