Download MendeleyStructural Basis of Low-pH-Dependent Lysosomal Cholesterol Egress by NPC1 and NPC2.
Qian, H., Wu, X., Du, X., Yao, X., Zhao, X., Lee, J., Yang, H., Yan, N.(2020) Cell 182: 98-111.e18
- PubMed: 32544384
- DOI: https://doi.org/10.1016/j.cell.2020.05.020
- Primary Citation of Related Structures:
6W5R, 6W5S, 6W5T, 6W5U, 6W5V - PubMed Abstract:
Lysosomal cholesterol egress requires two proteins, NPC1 and NPC2, whose defects are responsible for Niemann-Pick disease type C (NPC). Here, we present systematic structural characterizations that reveal the molecular basis for low-pH-dependent cholesterol delivery from NPC2 to the transmembrane (TM) domain of NPC1. At pH 8.0, similar structures of NPC1 were obtained in nanodiscs and in detergent at resolutions of 3.6 Å and 3.0 Å, respectively. A tunnel connecting the N-terminal domain (NTD) and the transmembrane sterol-sensing domain (SSD) was unveiled. At pH 5.5, the NTD exhibits two conformations, suggesting the motion for cholesterol delivery to the tunnel. A putative cholesterol molecule is found at the membrane boundary of the tunnel, and TM2 moves toward formation of a surface pocket on the SSD. Finally, the structure of the NPC1-NPC2 complex at 4.0 Å resolution was obtained at pH 5.5, elucidating the molecular basis for cholesterol handoff from NPC2 to NPC1(NTD).
Organizational Affiliation:
Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
