Structural insights into the interaction of human p97 N-terminal domain and SHP motif in Derlin-1 rhomboid pseudoprotease

The interaction of the rhomboid pseudoprotease Derlin-1 and p97 is crucial for the retrotranslocation of polyubiquitinated substrates in the endoplasmic reticulum-associated degradation pathway. We report a 2.25 angstrom resolution structure of the p97 N-terminal domain (p97N) in complex with the Derlin-1 SHP motif. Remarkably, the SHP motif adopts a short, antiparallel -strand that interacts with the -sheet of p97Na site distinct from that to which most p97 adaptor proteins bind. Mutational and biochemical analyses contributed to defining the specific interaction, demonstrating the importance of a highly conserved binding pocket on p97N and a signature motif on SHP. Our findings may also provide insights into the interactions between other SHP-containing proteins and p97N.