Architecture of the ESCPE-1 membrane coat

Using cryo-electron tomography, Lopez-Robles, Scaramuzza, Astorga-Simon, Ishida et al. solve the architecture of ESCPE-1, a protein scaffold that mediates the recycling of cargo from endosome to trans-Golgi network and plasma membrane in tubular carriers. Recycling of membrane proteins enables the reuse of receptors, ion channels and transporters. A key component of the recycling machinery is the endosomal sorting complex for promoting exit 1 (ESCPE-1), which rescues transmembrane proteins from the endolysosomal pathway for transport to the trans-Golgi network and the plasma membrane. This rescue entails the formation of recycling tubules through ESCPE-1 recruitment, cargo capture, coat assembly and membrane sculpting by mechanisms that remain largely unknown. Herein, we show that ESCPE-1 has a single-layer coat organization and suggest how synergistic interactions between ESCPE-1 protomers, phosphoinositides and cargo molecules result in a global arrangement of amphipathic helices to drive tubule formation. Our results thus define a key process of tubule-based endosomal sorting.

Automated summary

Using cryo-electron tomography, Lopez-Robles, Scaramuzza, Astorga-Simon, Ishida et al. solve the architecture of ESCPE-1, a protein scaffold that mediates the recycling of cargo from endosome to trans-Golgi network and plasma membrane in tubular carriers. The study reveals that ESCPE-1 has a single-layer coat organization and suggests that synergistic interactions between ESCPE-1 protomers, phosphoinositides, and cargo molecules drive tubule formation.