Back

Structural basis of an EMC:Spf1 insertase-dislocase complex in the eukaryotic endoplasmic reticulum

Klose, C. J.; Prabu, J. R.; Fenech, E. J.; Braeuning, B.; Baydar, I.; Steigenberger, B.; von Gronau, S.; Arad, S.; Langlois, C. R.; Schuldiner, M.; Schulman, B. A.; Feige, M. J.

2025-08-07 biochemistry
10.1101/2025.08.07.669073 bioRxiv
Show abstract

Most eukaryotic membrane proteins are inserted into the membrane at the endoplasmic reticulum (ER). This essential but error-prone process relies on molecular quality control machineries to prevent mistargeting and incorrect structure formation. Here we show that the ER membrane protein complex (EMC) forms an evolutionarily conserved supercomplex with the P5A-ATPase Spf1/ATP13A1. This supercomplex combines the transmembrane domain (TMD) insertase function of the EMC and the TMD dislocase activity of Spf1 in a single entity. Our cryo-EM structure of this supercomplex shows that EMC and Spf1 form a shared intramembrane cavity for substrate engagement and reveals that the ATPase cycle of Spf1 regulates access to this cavity. Together, our study suggests that proteins with opposing biochemical activities in membrane protein biogenesis - insertion versus dislocation - form an integrated molecular machine in eukaryotes to proofread membrane protein insertion and topogenesis.

Matching journals

The top 2 journals account for 50% of the predicted probability mass.

50% of probability mass above

"Similar papers" are the closest papers from that journal in the model's embedding space. They show what the match is built on, but the ranking comes mostly from a classifier over the whole training set, not from these examples alone.