scholarly journals Loss of intracellular lipid binding proteins differentially impacts saturated fatty acid uptake and nuclear targeting in mouse hepatocytes

2012 ◽  
Vol 303 (7) ◽  
pp. G837-G850 ◽  
Author(s):  
Stephen M. Storey ◽  
Avery L. McIntosh ◽  
Huan Huang ◽  
Gregory G. Martin ◽  
Kerstin K. Landrock ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Uptake ◽  
Lipid Binding ◽  
Acid Uptake ◽  
Nuclear Targeting ◽  
Fatty Acid Binding ◽  
Mouse Hepatocytes ◽  
Sterol Carrier Protein 2 ◽  
Lipid Binding Proteins ◽  
Lcfa Uptake

The liver expresses high levels of two proteins with high affinity for long-chain fatty acids (LCFAs): liver fatty acid binding protein (L-FABP) and sterol carrier protein-2 (SCP-2). Real-time confocal microscopy of cultured primary hepatocytes from gene-ablated (L-FABP, SCP-2/SCP-x, and L-FABP/SCP-2/SCP-x null) mice showed that the loss of L-FABP reduced cellular uptake of 12- N-methyl-(7-nitrobenz-2-oxa-1,3-diazo)-aminostearic acid (a fluorescent-saturated LCFA analog) by ∼50%. Importantly, nuclear targeting of the LCFA was enhanced when L-FABP was upregulated (SCP-2/SCP-x null) but was significantly reduced when L-FABP was ablated (L-FABP null), thus impacting LCFA nuclear targeting. These effects were not associated with a net decrease in expression of key membrane proteins involved in LCFA or glucose transport. Since hepatic LCFA uptake and metabolism are closely linked to glucose uptake, the effect of glucose on L-FABP-mediated LCFA uptake and nuclear targeting was examined. Increasing concentrations of glucose decreased cellular LCFA uptake and even more extensively decreased LCFA nuclear targeting. Loss of L-FABP exacerbated the decrease in LCFA nuclear targeting, while loss of SCP-2 reduced the glucose effect, resulting in enhanced LCFA nuclear targeting compared with control. Simply, ablation of L-FABP decreases LCFA uptake and even more extensively decreases its nuclear targeting.

Enterocyte fatty acid uptake and intestinal fatty acid-binding protein

2004 ◽  
Vol 32 (1) ◽  
pp. 75-78 ◽  
Author(s):  
P. Tso ◽  
A. Nauli ◽  
C.-M. Lo
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Binding Protein ◽  
Brush Border Membrane ◽  
Fatty Acid Uptake ◽  
Current Understanding ◽  
Fatty Acid Binding Proteins ◽  
Acid Uptake ◽  
Micellar Solubilization ◽  
Fatty Acid Binding

This article reviews our current understanding of the uptake of fatty acids by the enterocytes of the intestine. The micellar solubilization of fatty acids by bile salts and the factors regulating that process are discussed. The mechanism of how micellar solubilization of fatty acids promotes the uptake of fatty acids by enterocytes and their relative importance is reviewed. Additionally, discussion of the various fatty acid transporters located at the brush border membrane of the enterocytes is included. Finally, a summary of our current understanding of the function of fatty-acid-binding proteins inside enterocytes is provided.

Sex differences in hepatic fatty acid uptake reflect a greater affinity of the transport system in females

1992 ◽  
Vol 263 (3) ◽  
pp. G380-G385 ◽  
Author(s):  
D. Sorrentino ◽  
S. L. Zhou ◽  
E. Kokkotou ◽  
P. D. Berk
Keyword(s):  
Plasma Membrane ◽  
Fatty Acid ◽  
Transport System ◽  
Fatty Acid Uptake ◽  
Surface Expression ◽  
Female Rats ◽  
Acid Uptake ◽  
Fatty Acid Binding ◽  
Male And Female Rats

In this study, we examined the hypothesis that the reported sex difference in hepatic free fatty acid (FFA) uptake involves the putative FFA transport system, the plasma membrane fatty acid binding protein (FABPpm). In hepatocytes isolated from both male and female rats, initial [3H]oleate uptake velocity reflected transmembrane influx and not subsequent metabolism and was a saturable function of the unbound oleate concentration. Although Vmax values were similar (61 +/- 2 vs. 65 +/- 5 pmol.min-1.5 x 10(4) cells-1 for females and males, respectively), the apparent Km was significantly smaller in females (40 +/- 4 vs. 90 +/- 11 nM; P less than 0.05), reflecting faster influx velocities in female cells over a range of unbound oleate concentrations. The oleate efflux rate constant was also greater in females (0.280 +/- 0.014 vs. 0.198 +/- 0.020 min-1; P less than 0.05) despite their greater hepatic content of cytosolic FABP. Finally, despite the greater rates of transmembrane FFA flux in female hepatocytes, the surface expression of FABPpm was virtually identical in the two sexes (2.5 +/- 0.5 vs. 2.4 +/- 0.4 microgram/10(6) cells). Collectively, these data indicate that at FFA-to-albumin ratios occurring in vivo the plasma membrane of female hepatocytes transports oleate bidirectionally at a greater rate than that of male hepatocytes. A sex-related difference in the functional affinity of FABPpm for FFA appears the most likely explanation for the greater oleate uptake in females.

scholarly journals FATP2 is a hepatic fatty acid transporter and peroxisomal very long-chain acyl-CoA synthetase

2010 ◽  
Vol 299 (3) ◽  
pp. E384-E393 ◽  
Author(s):  
Alaric Falcon ◽  
Holger Doege ◽  
Amy Fluitt ◽  
Bernice Tsang ◽  
Nicki Watson ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Uptake ◽  
Fatty Acid Transport ◽  
Acid Uptake ◽  
Peroxisomal Enzyme ◽  
Multifunctional Protein ◽  
Hepatic Fatty Acid ◽  
Chain Acyl ◽  
Lcfa Uptake ◽  
Long Chain

Fatty acid transport protein (FATP)2, a member of the FATP family of fatty acid uptake mediators, has independently been identified as a hepatic peroxisomal very long-chain acyl-CoA synthetase (VLACS). Here we address whether FATP2 is 1) a peroxisomal enzyme, 2) a plasma membrane-associated long-chain fatty acid (LCFA) transporter, or 3) a multifunctional protein. We found that, in mouse livers, only a minor fraction of FATP2 localizes to peroxisomes, where it contributes to approximately half of the peroxisomal VLACS activity. However, total hepatic (V)LACS activity was not significantly affected by loss of FATP2, while LCFA uptake was reduced by 40%, indicating a more prominent role in hepatic LCFA uptake. This suggests FATP2 as a potential target for a therapeutic intervention of hepatosteatosis. Adeno-associated virus 8-based short hairpin RNA expression vectors were used to achieve liver-specific FATP2 knockdown, which significantly reduced hepatosteatosis in the face of continued high-fat feeding, concomitant with improvements in liver physiology, fasting glucose, and insulin levels. Based on our findings, we propose a model in which FATP2 is a multifunctional protein that shows subcellular localization-dependent activity and is a major contributor to peroxisomal (V)LACS activity and hepatic fatty acid uptake, suggesting FATP2 as a potential novel target for the treatment of nonalcoholic fatty liver disease.

Sign in / Sign up

Export Citation Format

Share Document