Inter-domain dynamics drive cholesterol transport by NPC1 and NPC1L1 proteins.

Piyali Saha, Justin L Shumate, Jenna G Caldwell, Nadia Elghobashi-Meinhardt, Albert Lu, Lichao Zhang, Niclas E Olsson, Joshua E Elias, Suzanne R Pfeffer

eLife 2020 May 15

filter terms:

Transport of LDL-derived cholesterol from lysosomes into the cytoplasm requires NPC1 protein; NPC1L1 mediates uptake of dietary cholesterol. We introduced single disulfide bonds into NPC1 and NPC1L1 to explore the importance of inter-domain dynamics in cholesterol transport. Using a sensitive method to monitor lysosomal cholesterol efflux, we found that NPC1's N-terminal domain need not release from the rest of the protein for efficient cholesterol export. Either introducing single disulfide bonds to constrain lumenal/extracellular domains or shortening a cytoplasmic loop abolishes transport activity by both NPC1 and NPC1L1. The widely prescribed cholesterol uptake inhibitor, ezetimibe, blocks NPC1L1; we show that residues that lie at the interface between NPC1L1's three extracellular domains comprise the drug's binding site. These data support a model in which cholesterol passes through the cores of NPC1/NPC1L1 proteins; concerted movement of various domains is needed for transfer and ezetimibe blocks transport by binding to multiple domains simultaneously. © 2020, Saha et al.

Citation

Piyali Saha, Justin L Shumate, Jenna G Caldwell, Nadia Elghobashi-Meinhardt, Albert Lu, Lichao Zhang, Niclas E Olsson, Joshua E Elias, Suzanne R Pfeffer. Inter-domain dynamics drive cholesterol transport by NPC1 and NPC1L1 proteins. eLife. 2020 May 15;9