The NPC1 protein: structure implies function

Biochim Biophys Acta. 2004 Oct 11;1685(1-3):8-13. doi: 10.1016/j.bbalip.2004.08.006.


Niemann-Pick type C (NPC) is a lysosomal storage disorder, characterized by intracellular accumulation of low-density lipoprotein (LDL)-derived cholesterol and neurodegeneration leading to premature death. The most common form of the disease, NPC1, results from mutations in the NPC1 gene. Thus, the NPC1 protein is the focus of intense investigation to elucidate the function of this protein and its role in the disease pathogenesis. Recent studies have revealed the NPC1 subcellular location, topology and potential functions of the NPC1 protein. In lieu of direct experimental evidence, certain hypotheses about the function of NPC1 can be inferred by analyzing disease-causing mutations, NPC1 protein sequence homology to other related proteins, and the potential tertiary structure similarity between NPC1 and its prokaryotic ancestors, such as the E. coli RND permease AcrB. This review will discuss recent work on the characterization and function of the NPC1 protein and highlight structural features that may be important in assisting in the elucidation of NPC1 function and role in subcellular lipid transport and homeostasis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cholesterol / metabolism
  • Endosomes / metabolism
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Membrane Glycoproteins / chemistry*
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Models, Biological
  • Molecular Sequence Data
  • Mutation
  • Niemann-Pick C1 Protein
  • Niemann-Pick Diseases / genetics
  • Niemann-Pick Diseases / metabolism*
  • Niemann-Pick Diseases / pathology
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Structure-Activity Relationship


  • Carrier Proteins
  • Intracellular Signaling Peptides and Proteins
  • Membrane Glycoproteins
  • NPC1 protein, human
  • Niemann-Pick C1 Protein
  • Cholesterol