Is the multidrug transporter a flippase?

Trends Biochem Sci. 1992 Jan;17(1):18-21. doi: 10.1016/0968-0004(92)90419-a.


The phenomenon of multidrug resistance is correlated with the presence of a membrane protein, P-glycoprotein, which pumps a wide variety of drugs out of cells thus reducing their toxicity. However, the mechanism of this pumping action remains unclear. In this article, we suggest that several properties of the multidrug transporter may be explained if it acts as a 'flippase' to transport drugs from the inner leaflet of the lipid bilayer to the outer or to the external medium.

Publication types

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

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Animals
  • Biological Transport, Active
  • Blood Proteins / physiology
  • Carrier Proteins / physiology
  • Drug Resistance / physiology
  • Humans
  • Ion Channels / physiology*
  • Membrane Glycoproteins / physiology*
  • Models, Biological
  • Neoplasm Proteins / physiology


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Blood Proteins
  • Carrier Proteins
  • Ion Channels
  • Membrane Glycoproteins
  • Neoplasm Proteins