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Cholesterol-7alpha-hydroxylase (CYP7A1) regulates the pathway through which cholesterol is converted into bile acids. The unique detergent properties of bile acids are essential for the digestion and intestinal absorption of hydrophobic nutrients. Bile acids have potent toxic properties (e.g., membrane disruption) and there are a plethora of mechanisms to(More)
Microsomal triglyceride transfer protein (MTP) is an intraluminal protein in the endoplasmic reticulum (ER) that is essential for the assembly of apolipoprotein B (apoB)-containing lipoproteins. In this study, we examine how the livers of mice respond to two distinct methods of blocking MTP function: Cre-mediated disruption of the gene for MTP and chemical(More)
Fatty acid transport protein (FATP), a plasma membrane protein implicated in controlling adipocyte transmembrane fatty acid flux, is up-regulated as a consequence of adipocyte differentiation and down-regulated by insulin. Based upon the sequence of the FATP gene upstream region (Hui, T. Y., Frohnert, B. I., Smith, A. J., Schaffer, J. A., and Bernlohr, D.(More)
Thioredoxin-interacting protein (Txnip) is a ubiquitous protein that binds with high affinity to thioredoxin and inhibits its ability to reduce sulfhydryl groups via NADPH oxidation. HcB-19 mice contain a nonsense mutation in Txnip that eliminates its expression. Unlike normal animals, HcB-19 mice have approximately 3-fold increase in insulin levels when(More)
L35 and FAO cells were derived as single cell isolates from H35 cells. Whereas L35 cells do not express microsomal triglyceride transfer protein (MTP), which regulates lipoprotein secretion, they express CYP7A1, which regulates bile acid synthesis from cholesterol. FAO cells display the opposite phenotype (i.e. expression of MTP but not CYP7A1). We examined(More)
A cDNA encoding a novel fatty acid transport protein (FATP) was identified recently using expression cloning methodologies. We have studied the expression of FATP in differentiating 3T3-L1 cells and adipose tissue in vivo. When 3T3-L1 preadipocytes are treated with a combination of methylisobutylxanthine, dexamethasone, and insulin to induce(More)
Fatty acid transport protein (FATP) was identified by expression cloning strategies (Schaffer, J. E., and Lodish, H. F. (1994) Cell 79, 427-436) and shown by transfection analysis to catalyze the transfer of long-chain fatty acids across the plasma membrane of cells. It is expressed highly in tissues exhibiting rapid fatty acid metabolism such as skeletal(More)
The insulin receptor, as a consequence of ligand binding, undergoes autophosphorylation of critical tyrosyl residues within the cytoplasmic portion of its beta-subunit. The 85 kDa regulatory subunit of phosphatidylinositol (PI) 3-kinase (p85), an SH2 domain protein, has been implicated as a regulatory molecule in the insulin signal transduction pathway. For(More)
Due to the absence of microsomal triglyceride transfer protein (MTP), Chinese hamster ovary (CHO) cells lack the ability to translocate apoB into the lumen of the endoplasmic reticulum, causing apoB to be rapidly degraded by an N-acetyl-leucyl-leucyl-norleucinal-inhibitable process. The goal of this study was to examine if expression of MTP, whose genetic(More)
The production of apolipoprotein B (apoB)-containing lipoproteins by the liver is regulated by a complex series of processes involving apoB being cotranslationally translocated across the endoplasmic reticulum and assembled into a lipoprotein particle. The translocation of apoB across the endoplasmic reticulum is facilitated by the intraluminal chaperone,(More)