The role of membranes and intracellular binding proteins in cytoplasmic transport of hydrophobic molecules: Fatty acid-binding proteins

Judith Storch, Fiona M. Herr, Kuo Tung Hsu, Hye Kyung Kim, Heng Ling Liou, Elizabeth R. Smith

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

The path of a small hydrophobic molecule through the aqueous cytoplasm is not linear. Partition may favor membrane binding by several orders of magnitude; thus significant membrane association will markedly decrease the cytosolic transport rate. The presence of high concentrations of soluble binding proteins for these hydrophobic molecules would compete with membrane association and thereby increase transport rate. For long chain fatty acid molecules, a family of cytosolic binding proteins collectively known as the fatty acid-binding proteins (FABP), ate thought to act as intracellular transport proteins. This paper examines the mechanism of transfer of fluorescent anthroyloxy-labeled fatty acids (AOFA) from purified FABP's to phospholipid vesicles. With the exception of the liver FABP, AOFA is transferted from FABP by collisional interaction of the protein with an acceptor membrane. The rate of transfer increased markedly when membranes contain anionic phospholipids; this suggests that positively charged residues on the surface of the FABP may interact with the membranes. Neutralization of surface lysine residues of adipocyte and heart-type FABPs decreased the AOFA transfer rate, and transfer was then found to proceed via aqueous diffusion rather than collisional interaction. Site-specific mutagenesis has further shown that the helix-turn-helix domain of the FABPs is critical for interaction with anionic acceptor membranes. In addition, direct interaction of adipocyte FABPs with anionic membranes has been demonstrated. Thus 'cytosolic' FABP may function in intracellular transport of fatty acids to decrease their membrane association, as well as to target fatty acids to specific subcellular sites of utilization.

Original languageEnglish
Pages (from-to)333-339
Number of pages7
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Volume115
Issue number3
DOIs
StatePublished - Dec 1 1996
Externally publishedYes

Fingerprint

Fatty Acid-Binding Proteins
Intracellular Membranes
Carrier Proteins
Membranes
Molecules
Fatty Acids
Adipocytes
Phospholipids
Mutagenesis
Site-Directed Mutagenesis
Lysine
Cytoplasm

Keywords

  • anionic phospholipids
  • binding proteins
  • fatty acids
  • fluorescent lipids
  • lipid transport
  • membrane-protein interactions
  • membranes

ASJC Scopus subject areas

  • Biochemistry
  • Physiology

Cite this

The role of membranes and intracellular binding proteins in cytoplasmic transport of hydrophobic molecules : Fatty acid-binding proteins. / Storch, Judith; Herr, Fiona M.; Hsu, Kuo Tung; Kim, Hye Kyung; Liou, Heng Ling; Smith, Elizabeth R.

In: Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology, Vol. 115, No. 3, 01.12.1996, p. 333-339.

Research output: Contribution to journalArticle

Storch, Judith ; Herr, Fiona M. ; Hsu, Kuo Tung ; Kim, Hye Kyung ; Liou, Heng Ling ; Smith, Elizabeth R. / The role of membranes and intracellular binding proteins in cytoplasmic transport of hydrophobic molecules : Fatty acid-binding proteins. In: Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology. 1996 ; Vol. 115, No. 3. pp. 333-339.
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