Zinc uptake into MCF-10A cells is inhibited by cholesterol depletion.
The mechanism for cellular Zn uptake was investigated by depleting cell cholesterol levels, a treatment that disrupts lipid rafts/caveolae-dependent processes and inhibits coated-pit budding. Incubation of MCF-10A human breast epithelial cells with hydroxypropyl-beta-cyclodextrin significantly lowered cell cholesterol levels and significantly inhibited cellular zinc uptake measured at 10 min, but had no effect on 2-deoxyglucose uptake. Replacing potassium for sodium in the uptake buffer significantly stimulated Zn uptake by 20%. The effects of potassium depletion and chlorpromazine on Zn uptake were investigated to determine the contribution of coated-pit endocytosis. Potassium depletion following hypotonic shock significantly inhibited Zn uptake into MCF-10A cells approximately 15%. Chlorpromazine at 20 microg/ml inhibited uptake approximately 30%. The data support the hypothesis that Zn uptake into MCF-10A cells involves lipid rafts/caveolae. The relatively mild effects of potassium depletion and chlorpromazine suggest that a small portion of Zn uptake may require coated pit endocytosis.
Mouat
Michael F
MF
University of Georgia, Department of Foods and Nutrition, Athens, GA 30602, USA.
Greenspan
Philip
P
Byerley
Lauri O
LO
Grider
Arthur
A
D000073738:2-Hydroxypropyl-beta-cyclodextrin; D001940:Breast / Q000378:metabolism*; D002461:Cell Line, Transformed; D002784:Cholesterol / Q000032:analysis*; D002966:Clathrin / Q000494:pharmacology; D003034:Coated Pits, Cell-Membrane / Q000187:drug effects; D003505:Cyclodextrins / Q000494:pharmacology; D003847:Deoxyglucose / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D007038:Hypotonic Solutions; D007700:Kinetics; D011188:Potassium / Q000032:analysis; D015032:Zinc / Q000378:metabolism*; D047392:beta-Cyclodextrins
D002966:Clathrin; D003505:Cyclodextrins; D007038:Hypotonic Solutions; D047392:beta-Cyclodextrins; D000073738:2-Hydroxypropyl-beta-cyclodextrin; D002784:Cholesterol; D003847:Deoxyglucose; D015032:Zinc; D011188:Potassium