Intracellular lipid-binding proteins and their genes.
Intracellular lipid-binding proteins are a family of low-molecular-weight single-chain polypeptides that form 1:1 complexes with fatty acids, retinoids, or other hydrophobic ligands. These proteins are products of a large multigene family of unlinked loci distributed throughout the genome. Each lipid-binding protein exhibits a distinctive pattern of tissue distribution. Transcriptional control, regulated by a combination of peroxisome proliferator activated receptors and CCAAT/enhancer-binding proteins, allows for a variety of both cell and tissue-specific expression patterns. In some cells, fatty acids increase the expression of the lipid-binding protein genes. Fatty acids, or their metabolites, are activators of the peroxisome proliferator-activated receptor family of transcription factors. Therefore, as the concentration of lipid in the diet increases, the expression of lipid-binding proteins coordinately increases. As revealed by X-ray crystallography, the lipid-binding proteins fold into beta-barrels, forming a large internal water-filled cavity. Fatty acid ligands are bound within the cavity, occupying only about one-third of the accessible volume. The bound fatty acid is stabilized via a combination of enthalpic and entropic forces that govern ligand affinity and selectivity. Cytoplasmic lipid-binding proteins are the intracellular receptors for hydrophobic ligands, delivering them to the appropriate site for use as metabolic fuels and regulatory agents.
Bernlohr
D A
DA
Department of Biochemistry, College of Biological Sciences, Institute of Human Genetics, Medical School, University of Minnesota, St. Paul 55108-1022, USA.
Simpson
M A
MA
Hertzel
A V
AV
Banaszak
L J
LJ
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017124:Conserved Sequence; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D018996:Myelin P2 Protein / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins
D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins