Structure of the Human Lipid Exporter ABCA1

Hongwu Qian, Xin Zhao, Pingping Cao, Jianlin Lei, Nieng Yan, Xin Gong

Research output: Contribution to journalArticlepeer-review

199 Scopus citations


ABCA1, an ATP-binding cassette (ABC) subfamily A exporter, mediates the cellular efflux of phospholipids and cholesterol to the extracellular acceptor apolipoprotein A-I (apoA-I) for generation of nascent high-density lipoprotein (HDL). Mutations of human ABCA1 are associated with Tangier disease and familial HDL deficiency. Here, we report the cryo-EM structure of human ABCA1 with nominal resolutions of 4.1 Å for the overall structure and 3.9 Å for the massive extracellular domain. The nucleotide-binding domains (NBDs) display a nucleotide-free state, while the two transmembrane domains (TMDs) contact each other through a narrow interface in the intracellular leaflet of the membrane. In addition to TMDs and NBDs, two extracellular domains of ABCA1 enclose an elongated hydrophobic tunnel. Structural mapping of dozens of disease-related mutations allows potential interpretation of their diverse pathogenic mechanisms. Structural-based analysis suggests a plausible “lateral access” mechanism for ABCA1-mediated lipid export that may be distinct from the conventional alternating-access paradigm.

Original languageEnglish (US)
Pages (from-to)1228-1239.e10
Issue number7
StatePublished - Jun 15 2017

All Science Journal Classification (ASJC) codes

  • General Biochemistry, Genetics and Molecular Biology


  • ABC transporters
  • ABCA1
  • Tangier disease
  • cryo-EM structure
  • familial HDL deficiency
  • lipid exporter
  • nascent HDL formation
  • reverse cholesterol transport


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