Triazoles inhibit cholesterol export from lysosomes by binding to NPC1

Michael N. Trinha, Feiran Lua, Xiaochun Lib, Akash Dasa, Qiren Liangd, Jef K. De Brabanderd, Michael S. Browna, Joseph L. Goldsteina

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Niemann-Pick C1 (NPC1), a membrane protein of lysosomes, is required for the export of cholesterol derived from receptor-mediated endocytosis of LDL. Lysosomal cholesterol export is reportedly inhibited by itraconazole, a triazole that is used as an antifungal drug [Xu et al. (2010) Proc Natl Acad Sci USA 107:4764-4769]. Here we show that posaconazole, another triazole, also blocks cholesterol export from lysosomes. We prepared P-X, a photoactivatable cross-linking derivative of posaconazole. P-X cross-linked to NPC1 when added to intact cells. Cross-linking was inhibited by itraconazole but not by ketoconazole, an imidazole that does not block cholesterol export. Cross-linking of P-X was also blocked by U18666A, a compound that has been shown to bind to NPC1 and inhibit cholesterol export. P-X also crosslinked to purified NPC1 that was incorporated into lipid bilayer nanodiscs. In this in vitro system, cross-linking of P-X was inhibited by itraconazole, but not by U18666A. P-X cross-linking was not prevented by deletion of the N-terminal domain of NPC1, which contains the initial binding site for cholesterol. In contrast, P-X cross-linking was reduced when NPC1 contained a point mutation (P691S) in its putative sterolsensing domain. We hypothesize that the sterol-sensing domain has a binding site that can accommodate structurally different ligands.

Original languageEnglish (US)
Pages (from-to)89-94
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number1
StatePublished - Jan 3 2017


  • Cholesterol transport
  • Lipid nanodiscs
  • Niemann-Pick C disease
  • Photoactivatable cross-linking
  • Sterol-sensing domain

ASJC Scopus subject areas

  • General


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