14 research outputs found
Genetic diversity and evidence of recent demographic expansion in waterbird populations from the Brazilian Pantanal
Characterization of sites with elevated LDL permeability at intercostal, celiac, and iliac branches of the normal rabbit aorta.
Measurement of endothelial permeability to 125I-low density lipoproteins in rabbit arteries by use of en face preparations.
Prolonged Ethanol Consumption Produces Persistent Alterations of Cholinergic Function in Rat Brain
Association of TM4SF4 with the Human Thiamine Transporter-2 in Intestinal Epithelial Cells
BACKGROUND: The human thiamine transporter-2 (hTHTR-2) is involved in the intestinal absorption of thiamine. Recent studies with membrane transporters of other nutrients/substrates have shown that they have associated proteins that affect different aspects of their physiology and cell biology. Nothing is known about protein(s) that interact with hTHTR-2 in intestinal epithelial cells and influence its physiological function and/or its cell biology. AIMS: The aim of this study was to identify protein partner(s) that interacts with hTHTR-2 in human intestinal cells and determine the physiological/biological consequence of that interaction. METHODS: The yeast split-ubiquitin two-hybrid approach was used to screen a human intestinal cDNA library. GST-pull-down and cellular co-localization approaches were used to confirm the interaction between hTHTR-2 and the associated protein(s). The effect of such an interaction on hTHTR-2 function was examined by (3)H-thiamine uptake assays. RESULTS: Our screening results identified the human TransMembrane 4 SuperFamily 4 (TM4SF4) as a potential interactor with hTHTR-2. This interaction was confirmed by an in vitro GST-pull-down assay, and by live-cell confocal imaging of HuTu-80 cells co-expressing hTHTR-2-GFP and mCherry-TM4SF4 (the latter displayed a significant overlap of these two proteins in intracellular vesicles and at the cell membrane). Co-expression of hTHTR-2 with TM4SF4 in HuTu-80 cells led to a significant induction in thiamine uptake. In contrast, silencing TM4SF4 with gene-specific siRNA led to a significant decrease in thiamine uptake. CONCLUSIONS: These results show for the first time that the accessory protein TM4SF4 interacts with hTHTR-2 and influences the physiological function of the thiamine transporter