Role Of Fatty Acid Binding Protein Research Articles

Effect of host fatty acid-binding protein and fatty acid uptake on growth of Chlamydia trachomatis L2

Chlamydia trachomatis is an obligate intracellular bacterium and acquires both building blocks and energy from host cells for growth. The fatty acid-binding protein (FABP) plays an important role in uptake of long-chain fatty acids (LCFA) and energy metabolism by eukaryotic cells. The roles of FABP and LCFA in chlamydial infection were evaluated. Infection of liver cells with chlamydial organisms promoted fatty acid uptake by the infected cells, suggesting that LCFA may benefit chlamydial growth. Introduction of FABP into the liver cells not only enhanced fatty acid uptake, but also increased chlamydial intravacuolar replication and maturation. The FABP-enhanced chlamydial intracellular growth was dependent on the host cell uptake of fatty acids. These results have demonstrated that C. trachomatis can productively infect liver cells and utilize FABP-transported LCFA for its own biosynthesis.

Inversely related expression of epidermal- and heart-type fatty acid binding proteins during myogenic differentiation of C2C12 myoblasts

Following our report that heart-type (H-) fatty acid binding protein (FABP) was strongly up-regulated in differentiating myotubes, we examined the role of FABP and their effect on oleic acid uptake in the differentiation of mouse C2C12 myoblasts to myotubes in vitro. A second epidermal-type (E-) FABP is already expressed in the myoblast stage and is down-regulated at the onset of myogenic differentiation. This down-regulation is paralleled by that of β-actin, whereas mRNA expression of myogenic transcription factors and of H-FABP increases. These findings were verified at the protein level, which indicated that a basal level of FABPs, independent of the type, is always present during differentiation. Both FABPs were identified by their intracellular binding of oleic acid. This may explain that the change in oleic acid uptake into C2C12 cells at different stages of differentiation was negligible. Yet, the transition from E-FABP expressing myoblasts to H-FABP expressing myotubes was accompanied by a shift in preferential incorporation of oleic acid from triacylglycerols to phospholipids, perhaps necessary for terminal differentiation. The comparison of the expression of H-FABP with that of master myogenic transcription factors demonstrates that this fatty acid binding protein is not involved in the initiation of differentiation. The combination of a particular FABP and the cell in which it is expressed determines the fatty acid uptake. Cette etude examine le role des proteines de liaison des acides gras (FABP) de type cardiaque et leur effet sur la captation de l'acide oleique dans la differenciation de myoblastes C2C12 de souris en myotubes in vitro. Une FABP de type epidermique est exprimee au stade myoblaste et diminue au debut de la differenciation myogenique. Cette regulation est parallele a celle de la β-actine alors que l'expression de l'ARNm des facteurs de transcription myogenique et les FABP du type cardiaque augmentent. Les resultats montrent que ces proteines de liaison des acides gras ne sont pas impliquees dans la differenciation terminale.

Developmental role of fatty acid-binding proteins in mouse brain

While the functions of the cytoplasmic fatty acid-binding proteins (FABPs) are not well defined, one possibility in neural tissue is in establishing and maintaining the high levels of polyunsaturated fatty acids in membrane lipids characteristic of this tissue and thought essential for normal function. We investigated the reactivity of a protein in developing mouse brain to antiserum prepared against rat heart (H)-FABP. By immunoblot analysis, levels of H-FABP in brain were nearly undetectable until fetal day 17–19, after which levels increased until at least postnatal day 14. Levels of H-FABP were lower in the adult mouse brain, suggesting a function for the protein during differentiation of neural tissue. In immunohistochemical studies with postnatal day 14 mouse brain, the most intensely stained area was the choroid plexus. H-FABP also localized to regions of the somatosensory cortex and to the spinal trigeminal nucleus. In addition, H-FABP was present in the thalamus, entorhinal and piriform cortex, and throughout the pontine and medullary nuclei. Tracts related to the auditory system, including ventral cochlear nucleus and lateral lemniscus, also were H-FABP-positive. In cerebellum, the molecular layer was heavily labeled in cells and processes; in the granule cell layer, there was punctate staining suggestive of mossy fiber terminals. Small cells adjacent to Purkinje cells were intensely stained, while the Purkinje cells were negative. We conclude that H-FABP in brain participates in neurite formation and synapse maturation, and may be related to the similar pattern of expression of GABA related markers.

Role of fatty acid-binding protein in lipid metabolism of insect flight muscle.

Since insect flight muscles are among the most active muscles in nature, their extremely high rates of fuel supply and oxidation pose interesting physiological problems. Long-distance flights of species like locusts and hawkmoths are fueled through fatty acid oxidation. The lipid substrate is transported as diacylglycerol in the blood, employing a unique and efficient lipoprotein shuttle system. Following diacyglycerol hydrolysis by a flight muscle lipoprotein lipase, the liberated fatty acids are ultimately oxidized in the mitochondria. Locusta flight muscle cytoplasm contains an abundant fatty acid-binding protein (FABP). The flight muscle FABP of Locusta migratoria is a 15 kDa protein with an isoelectric point of 5.8, binding fatty acids in a 1:1 molar stoichiometric ratio. Binding affinity of the FABP for long-chain fatty acids (apparent dissociation constant Kd = 5.21 +/- 0.16 microM) is however markedly lower than that of mammalian FABPs. The NH2-terminal amino acid sequence shares structural homologies with two insect FABPs recently purified from hawkmoth midgut, as well as with mammalian FABPs. In contrast to all other isolated FABPs, the NH2 terminus of locust flight muscle FABP appeared not to be acetylated. During development of the insect, a marked increase in fatty acid binding capacity of flight muscle homogenate was measured, along with similar increases in both fatty acid oxidation capacity and citrate synthase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Diversity of fatty acid-binding protein structure and function: studies with fluorescent ligands.

The mammalian fatty acid-binding proteins (FABP) are localized in many distinct cell types. They bind long chain fatty acids in vitro, however, their functions and mechanisms of action in vivo remain unknown. The present studies have sought to understand the relationships among these proteins, and to address the possible role of FABP in cellular fatty acid traffic. A series of anthroyloxy-labeled fluorescent fatty acids have been used to examine the physicochemical properties of the fatty acid-binding sites of different members of the FABP family. The fatty acid probes have also been used to study the rate and mechanism of fatty acid transfer from different FABP types to phospholipid membranes. The results of these studies show a number of interesting and potentially important differences between FABP family members. An examination of adipocyte and heart FABP (A- and H-FABP) shows that their fatty acid-binding sites are less hydrophobic than the liver FABP (L-FABP) site, and that the bound ligand experiences less motional constraint within the A- and H-FABP binding sites than within the L-FABP binding site. In keeping with these differences in structural properties, it was found that anthroyloxy-fatty acid transfer from A- and H-FABP to membranes is markedly faster than from L-FABP. Moreover, the mechanism of fatty acid transfer was found to be similar for the highly homologous A- and H-FABP, whereby transfer to phospholipid membranes appears to occur via transient collisional interactions between the FABP and membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Protective role of fatty acid-binding protein in ischemic and reperfused heart.

HomeCirculation ResearchVol. 68, No. 5Protective role of fatty acid-binding protein in ischemic and reperfused heart. Free AccessAbstractPDF/EPUBAboutView PDFSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessAbstractPDF/EPUBProtective role of fatty acid-binding protein in ischemic and reperfused heart. J F Glatz, G J van der Vusse and R S Reneman J F GlatzJ F Glatz Search for more papers by this author , G J van der VusseG J van der Vusse Search for more papers by this author and R S RenemanR S Reneman Search for more papers by this author Originally published1 May 1991https://doi.org/10.1161/01.RES.68.5.1490Circulation Research. 1991;68:1490–1491"Protective role of fatty acid-binding protein in ischemic and reperfused heart.." Circulation Research, 68(5), pp. 1490–1491 Previous Back to top Next FiguresReferencesRelatedDetails May 1, 1991Vol 68, Issue 5 Advertisement Article InformationMetrics Copyright © 1991 by American Heart Associationhttps://doi.org/10.1161/01.RES.68.5.1490 Originally publishedMay 1, 1991 PDF download Advertisement

Role of fatty acid-binding protein in cardiac fatty acid oxidation

Although abundant in most biological tissues and chemically well characterized, the fatty acid-binding protein (FABP) was until recently in search of a function. Because of its strong affinity for long chain fatty acids and its cytoplasmic origin, this protein was repeatedly claimed in the literature to be the transcytoplasmic fatty acid carrier. However, techniques to visualize and quantify the movements of molecules in the cytoplasm are still in their infancy. Consequently the carrier function of FABP remains somewhat speculative. However, FABP binds not only fatty acids but also their CoA and carnitine derivatives, two typical molecules of mitochondrial origin. Moreover, it has been demonstrated and confirmed that FABP is not exclusively cytoplasmic, but also mitochondrial. A function for FABP in the mitochondrial metabolism of fatty acids plus CoA and carnitine derivatives would therefore be anticipated. Using spin-labelling techniques, we present here evidence that FABP is a powerful regulator of acylcarnitine flux entering the mitochondrial beta-oxidative system. In this perspective FABP appears to be an active link between the cytoplasm and the mitochondria, regulating the energy made available to the cell. This active participation of FABP is shown to be the consequence of its gradient-like distribution in the cardiac cell, and also of the coexistence of multispecies of this protein produced by self-aggregation.

A novel role of fatty acid-binding protein as a vehicle of retinoids

Intracellular transport and storage of retinoids were shown to be conducted by fatty acid-binding protein (FABP). When rat liver cytosol was gel filtrated, retinyl palmitate-binding activity was mainly eluted in the fraction with a Mr. of around 14,000, in which both FABP and cellular retinol-binding protein (CRBP) co-existed. From the binding analysis of purified FABP and CRBP to retinyl palmitate, FABP was found to have a relatively high affinity (Kd = 1.4 X 10(-6) M) to retinyl palmitate, while binding of retinyl palmitate to CRBP was scarcely detectable. By using anti-FABP serum, it was shown that FABP was distributed in organs relating to absorption and storage of retinoids, such as jejunum, ileum, and liver. In liver, the protein was localized in the parenchymal cells and with particularly high concentration in the perisinusoidal cells, probably fat-storing cells.

Fatty acid transport in muscle: the role of fatty acid-binding proteins.

Fatty acid transport in muscle: the role of fatty acid-binding proteins.

Measurement of rat heart fatty acid binding protein by ELISA. Tissue distribution, developmental changes and subcellular distribution

A class of soluble, low molecular weight proteins collectively called fatty acid binding proteins (FABP) are thought to function in the intracellular movement of fatty acids. To understand more clearly the role of FABP in cardiac metabolism, we used ELISA and immunoblotting techniques to study the distribution of heart FABP in several rat tissues, compare male and female rat heart content, quantitate developmental changes, and determine its subcellular distribution. Immunoreactive protein was found in appreciable amounts in rat heart, red skeletal muscle and kidney. Adult rat heart contained about 1.5 mg FABP/g tissue wet weight with the atrial content being approximately 50% of the ventricular concentration. No significant difference was detected between the sexes. The amount of FABP increased progressively during development from fetal to adult animals, and measureable amounts were found in 17-day-old fetal tissue. Comparisons between myoglobin and FABP showed that FABP appeared earlier than myoglobin in development, but myoglobin was more abundant than FABP at birth. Using immunoblots it was determined that rat heart FABP was localized in the cytosol with no detectable intramitochondrial material.