Functions of fatty acid binding proteins

Abstract

Cytosolic fatty acid binding proteins (FABP) belong to a gene family of which eight members have been conclusively identified. These 14-15 kDa proteins are abundantly expressed in a highly tissue-specific manner. Although the functions of the cytosolic FABP are not clearly established, they appear to enhance the transfer of long-chain fatty acids between artificial and native lipid membranes, and also to have a stimulatory effect on a number of enzymes of fatty acid metabolism in vitro. These findings, as well as the tissue expression, ligand binding properties, ontogeny and regulation of these proteins provide a considerable body of indirect evidence supporting a broad role for the FABP in the intracellular transport and metabolism of long-chain fatty acids. The available data also support the existence of structure- and tissue-specific specialization of function among different members of the FABP gene family. Moreover, FABP may also have a possible role in the modulation of cell growth and proliferation, possibly by virtue of their affinity for ligands such as prostaglandins, leukotrienes and fatty acids, which are known to influence cell growth activity. FABP structurally unrelated to the cytosolic gene family have also been identified in the plasma membranes of several tissues (FABPpm). These proteins have not been fully characterized to date, but strong evidence suggest that they function in the transport of long-chain fatty acids across the plasma membrane.

Sm14 gene expression in different stages of the Schistosoma mansoni life cycle and immunolocalization of the Sm14 protein within the adult worm

“…Thus, our findings bring new insights into the localization and putative function of Sm14 in S. mansoni. The localization of Sm14 shown in this study is related to other FABPs, which are preferably localized in tissues with a high flow of or demand for fatty acids (10). In mammals, there are three major cytoplasmic FABPs: intestinal, heart and liver FABPs.…”

“…FABPs appear to be involved in the acquisition and utilization of fatty acids in different organisms (10). There are at least two main classes of FABPs, a cytoplasmic and a plasmalemmal FABP (11).…”

The Crystal Structure of the Liver Fatty Acid-binding Protein

“…This density was ultimately modeled by one molecule of butanoic acid. Additional ͉͉F o ͉ Ϫ ͉F c ͉͉ electron density (3 ) found adjoining that of one of the oleic acid molecules near its -terminal end was also definitely nonsolvent in nature. This density proved difficult to interpret and was modeled by a single carbon pseudoatom.…”

“…The functions of LFABP, like other family members, are thought to include lipid uptake, lipid transport, regulation of lipid metabolism, and cellular protection by maintaining the concentrations of free cytosolic fatty acids below toxic levels (3). The iLBP family is characterized by their small size of approximately 130 amino acids, their affinity for hydrophobic molecules, and their tertiary structure.…”

“…In addition to fatty acids, their CoA esters, and lysophosphatidic acid, LFABP also binds heme, squalene, certain eicosanoids, bilirubin, and a host of other hydrophobic compounds (3,4,(11)(12)(13)(14). Whether LFABP binds cholesterol is uncertain.…”