A major superfamily of transmembrane facilitators that catalyse uniport, symport and antiport

Trends Biochem Sci. 1993 Jan;18(1):13-20. doi: 10.1016/0968-0004(93)90081-w.


Many transport proteins of bacteria and eukaryotes are thought to possess a common structural motif of 12 transmembrane-spanning alpha-helical segments. In this report we use statistical methods to establish that five families or clusters of these facilitators comprise a single superfamily. The five clusters include: (1) drug-resistance proteins, (2) sugar facilitators, (3) facilitators for Krebs cycle intermediates, (4) phosphate ester-phosphate antiporters and (5) a distinct group of oligosaccharide-H+ symporters. Over 50 transporters of bacteria, lower eukaryotes, plants and animals, and one putative bacterial transcriptional regulatory protein are members of this superfamily, which we term the 'major facilitator superfamily' (MFS).

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bacterial Proteins / genetics
  • Biological Transport, Active
  • Carrier Proteins / genetics
  • Genes, Regulator
  • Humans
  • Ion Transport*
  • Molecular Sequence Data
  • Monosaccharide Transport Proteins / genetics*
  • Repressor Proteins / genetics*


  • Bacterial Proteins
  • Carrier Proteins
  • Monosaccharide Transport Proteins
  • Repressor Proteins