Disease relevance of Fabp6

• To compare steady-state levels of these gamma GT RNAs in rat tissues, hepatic carcinomas, and cultured cells, we used RNA dot-blot hybridization and a reverse transcriptase-polymerase chain reaction (RT-PCR) technique with oligonucleotides specifically designed for each type of RNA [1].
• Administration of gentamicin at 100 mg/kg, s.c. for 5 days to rats induced a marked renal failure, characterised by a significant decrease in creatinine clearance and increased plasma creatinine levels, fractional excretion of sodium, lithium, urine gamma glutamyl transferase (gamma GT) and daily urine volume [2].
• Glutathione monoethyl ester (GME) administration alone reduced proteinuria by 21% in AN, which was not significant despite a large increase in the renal GSH content, however, GP and GT activities were not increased by GME [3].
• Changes in expression of the mRNAs for L-FABP (liver fatty acid binding protein) and ILBP (ileal lipid binding protein) did not explain these alterations in lipid uptake [4].

High impact information on Fabp6

• The level of labyrinthine GT3 mRNA showed no change from midgestation through term; however, the volume of the labyrinth and hence total GT 3 gene expression increased greatly during this period [5].
• Since this effect can occur without alteration in the expression of the two species of glucose transporters present in adipose cells or in their translocation to the plasma membrane in response to insulin, it may result from changes in GT functional activity [6].
• Levels of the HepG2/brain GT protein and mRNA are unaltered by diabetes or phlorizin treatment [6].
• Importantly, levels of the adipose/muscle GT protein remain 43% reduced in the low-density microsomes in the basal state and 46% reduced in the plasma membranes in the insulin-stimulated state [6].
• Gelshift assays with nuclear extracts from rat ileum at different ages revealed absence of the DNA/protein complex in the second postnatal week when there is lack of IBABP expression and presence of these complexes at later ages when there is normally high expression [7].

Biological context of Fabp6

• After sequencing of rat Fabp6, the gene was localized in a radiation hybrid (RH) map on chromosome 10 [8].
• The intronless Fabp6 segment, which might be a pseudogene of Fabp6, was localized on rat chromosome 15 [8].
• Molecular cloning, tissue distribution, and expression of a 14-kDa bile acid-binding protein from rat ileal cytosol [9].
• Transfection of the I-BABP cDNA into COS-7 cells resulted in the expression of a 14-kDa protein that was identical to the ileal cytosolic I-BABP as determined by immunoblotting [9].
• The nucleotide sequence of the open reading frame exhibited 79% identity to that of the porcine gastrotropin [10].

Anatomical context of Fabp6

• Northern blot analysis revealed a single transcript of approximately 0.5 kb in ileum and ovary; however, the abundance of I-BABP mRNA was much greater in ileum than in ovary [9].
• The deduced sequence of 127 amino acids was identical to that of rat I-15P which was purified from rat intestinal epithelium [10].
• This high level of homology together with other features of I-BABP identify it as rat gastrotropin, establishing gastrotropin as the major intracellular bile acid carrier of rat enterocytes [11].
• METHODS: Small and large cholangiocytes or intrahepatic bile duct units (IBDUs) were isolated from normal rats, and gene expression for the apical Na+-dependent bile acid transporter (ABAT) and the 14-kilodalton ileal cytosolic binding protein (IBABP) was assessed by ribonuclease-protection assays [12].
• We and others have previously shown that, after exposure to phorbol esters, cultured fibroblasts exhibit increased expression of the mRNA encoding the HepG2/brain glucose transporter (GT mRNA) [13].

Associations of Fabp6 with chemical compounds

• Northern blot analysis indicated that the same size of transcript as that of the ileum was detected in the ovary, suggesting that I-15P or a homologous protein might be involved in the metabolism of steroids in steroid hormone-producing tissues [10].
• RESULTS: Taurocholate gavage significantly elevated IBABP messenger RNA and protein levels in suckling animals [7].
• RESULTS: Cal I-1 significantly reduced I/R-mediated increases in urea, creatinine, gamma GT, AST, NAG, and FE(Na) and significantly improved C(Cr) [14].
• Western blot analysis indicated increased levels of gamma GT protein with increasing menadione [15].
• Plasma concentrations of urea, creatinine, Na(+), gamma-glutamyl transferase (gamma GT), aspartate aminotransferase (AST) and urinary Na(+), glutathione S-transferase (GST), and N-acetyl-beta-D-glucosaminidase (NAG) were measured for the assessment of renal dysfunction and I/R injury [14].

Other interactions of Fabp6

• These studies have isolated a 14 kDa bile acid-binding protein from rat ileal cytosol which is immunologically and biochemically distinct from I-FABP and L-FABP [16].
• RESULTS: Transport, apical sodium-dependent bile acid transporter and ileal lipid-binding protein messenger RNA and protein expression were restricted to the distal 30 cm of ileum [17].

Analytical, diagnostic and therapeutic context of Fabp6

• Enzymatic digestion of I-BABP which had been electroblotted to nitrocellulose led to the recovery and sequence analysis of four peptides representing 47 residues of sequence (approximately 35% of the full sequence) [11].
• The 14 kDa bile acid binding protein of rat ileal cytosol (I-BABP), previously shown to be the major intracellular transporter of bile acids in enterocytes, was purified by affinity chromatography and gel electrophoresis [11].
• The gamma GT activity, P(up)(tot) and P(up)(gamma GT) (assessed by inhibiting gamma GT) were measured immediately after the exposure to hyperoxia, or 24 hr after treatment with BSO, t-BOOH or PQ [18].
• Therefore, carbohydrate epitope on lipids, as opposed to that on proteins, may be preferentially detectable by immunocytochemistry after fixation with 2% or 4% GT/PF [19].
• Immuno-electron microscopy further demonstrated that I-15P is localized in both the cytoplasmic and nuclear matrix regions of these cells [20].

References