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Hepcidin is a peptide hormone secreted by the liver in response to iron loading and inflammation. Decreased hepcidin leads to tissue iron overload, whereas hepcidin overproduction leads to hypoferremia and the anemia of inflammation. Ferroportin is an iron exporter present on the surface of absorptive enterocytes, macrophages, hepatocytes, and placental(More)
Hemoproteins are critical for the function and integrity of aerobic cells. However, free heme is toxic. Therefore, cells must balance heme synthesis with its use. We previously demonstrated that the feline leukemia virus, subgroup C, receptor (FLVCR) exports cytoplasmic heme. Here, we show that FLVCR-null mice lack definitive erythropoiesis, have(More)
We identified VTA1 in a screen for mutations that result in altered vacuole morphology. Deletion of VTA1 resulted in delayed trafficking of the lipophilic dye FM4-64 to the vacuole and altered vacuolar morphology when cells were exposed to the dye 5-(and 6)-carboxy-2',7'-dichlorofluorescein diacetate (CDCFDA). Deletion of class E vacuolar protein sorting(More)
Celecoxib pharmacokinetics was evaluated after single and multiple oral dosing; after dosing in a solution and as a solid; with and without food; and after administration into different sites of the GI tract using dog. After oral dosing in a solution, celecoxib was rapidly absorbed and reached maximum concentrations by 1 h; absorption was delayed another 1(More)
Ferroportin (Fpn) is the only known iron exporter in vertebrates. Hepcidin, a peptide secreted by the liver in response to iron or inflammation, binds to Fpn, inducing its internalization and degradation. We show that after binding of hepcidin, Fpn is tyrosine phosphorylated at the plasma membrane. Mutants of human Fpn that do not get internalized or that(More)
We examined the function of LIP5 in mammalian cells, because the yeast homologue Vta1p was recently identified as a protein required for multivesicular body (MVB) formation. LIP5 is predominantly a cytosolic protein. Depletion of LIP5 by small inhibitory RNA (siRNA) does not affect the distribution or morphology of early endosomes, lysosomes, or Golgi but(More)
The term hemochromatosis represents a group of inherited disorders leading to iron overload. Mutations in HFE, HJV, and TfR2 cause autosomal-recessive forms of hemochromatosis. Mutations in ferroportin, however, result in dominantly inherited iron overload. Some mutations (H32R and N174I) in ferroportin lead to macrophage iron loading, while others (NI44H)(More)
Mutations in the Chediak-Higashi syndrome gene (CHS1) and its murine homologue Beige result in the formation of enlarged lysosomes. BPH1 (Beige Protein Homologue 1) encodes the Saccharomyces cerevisiae homologue of CHS1/Beige. BPH1 is not essential and the encoded protein was found to be both cytosolic and peripherally bound to a membrane. Neither(More)
Ferritin is a cytosolic molecule comprised of subunits that self-assemble into a nanocage capable of containing up to 4500 iron atoms. Iron stored within ferritin can be mobilized for use within cells or exported from cells. Expression of ferroportin (Fpn) results in export of cytosolic iron and ferritin degradation. Fpn-mediated iron loss from ferritin(More)
The Chediak-Higashi Syndrome (CHS) and the orthologous murine disorder beige are characterized at the cellular level by the presence of giant lysosomes. The CHS1/Beige protein is a 3787 amino acid protein of unknown function. To determine functional domains of the CHS1/Beige protein, we generated truncated constructs of the gene/protein. These truncated(More)