Membrane topology distinguishes a subfamily of the ATP-binding cassette (ABC) transporters

FEBS Lett. 1997 Jan 27;402(1):1-3. doi: 10.1016/s0014-5793(96)01478-0.


A group of ATP-binding cassette (ABC) transporters, including the yeast cadmium transporter (YCF1), the mammalian multidrug resistance-associated protein (MRP), the multispecific organic anion transporter and its congener (MOAT and EBCR), as well as the sulfonylurea receptor (SUR), group into a subfamily by sequence comparison. We suggest that these MRP-related proteins are also characterized by a special, common membrane topology pattern. The most studied ABC transporters, the cystic fibrosis transmembrane conductance regulator (CFTR) and the multidrug resistance (MDR) proteins, were shown to contain a tandem repeat of six transmembrane helices, each set followed by an ATP-binding domain. According to the present study, in contrast to various membrane topology predictions proposed for the different MRP-related proteins, they all seem to have a CFTR/MDR-like core structure, and an additional, large, N-terminal hydrophobic region. This latter domain is predicted to contain 4-6 (most probably 5) transmembrane helices, and is occasionally glycosylated on the cell surface. Since all the MRP-related transporters were shown to interact with anionic compounds, the N-terminal membrane-bound domain may have a key role in these interactions.

Publication types

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

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry*
  • ATP-Binding Cassette Transporters / metabolism
  • Cell Membrane / metabolism*
  • Glycosylation
  • Molecular Sequence Data
  • Multidrug Resistance-Associated Proteins
  • Protein Structure, Secondary


  • ATP-Binding Cassette Transporters
  • Multidrug Resistance-Associated Proteins