Binding of sulfosuccinimidyl fatty acids to adipocyte membrane proteins: isolation and amino-terminal sequence of an 88-kD protein implicated in transport of long-chain fatty acids

J Membr Biol. 1993 Apr;133(1):43-9. doi: 10.1007/BF00231876.

Abstract

We recently reported (Harmon et al., J. Membrane Biol. 124:261-268, 1991) that sulfo-N-succinimidyl derivatives of long-chain fatty acids (SS-FA) specifically inhibited transport of oleate by rat adipocytes. These compounds bound to an 85-90 kD membrane protein which was also labeled by another inhibitor of FA transport [3H]DIDS (4,4'-diisothiocyanostilbene-2-2'-sulfonate). These results indicated that the protein was a strong candidate as the transporter for long-chain fatty acids. In this report we determined that the apparent size of the protein is 88 kD and its isoelectric point is 6.9. We used [3H]SS-oleate (SSO), which specifically labels the 88-kD protein, to isolate it from rat adipocyte plasma membranes. Identification of 15 amino acids at the N-terminus region revealed strong sequence homology with two previously described membrane glycoproteins: CD36, a ubiquitous protein originally identified in platelets and PAS IV, a protein that is enriched in the apical membranes of lipid-secreting mammary cells during lactation. Antibody against PAS IV cross-reacted with the adipocyte protein. This, together with the N-terminal sequence homology, suggested that the adipocyte protein belongs to a family of related intrinsic membrane proteins which include CD36 and PAS IV.

MeSH terms

  • Adipose Tissue / metabolism*
  • Amino Acid Sequence
  • Animals
  • Cattle
  • Cell Membrane / metabolism
  • Fatty Acids / metabolism*
  • Humans
  • Immunoblotting
  • In Vitro Techniques
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / isolation & purification
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Molecular Weight
  • Protein Binding
  • Rats
  • Rats, Sprague-Dawley
  • Sequence Homology, Amino Acid
  • Succinimides

Substances

  • Fatty Acids
  • Membrane Proteins
  • Succinimides