Receptor-mediated uptake of ferritin-bound iron by human intestinal Caco-2 cells.
Receptor-mediated uptake of ferritin-bound iron by human intestinal Caco-2 cells.
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DOI：
10.1016/j.jnutbio.2008.04.003
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发表时间：
2009-04
影响因子：
5.6
通讯作者：
Lonnerdal, Bo
中科院分区：
文献类型：
--
作者：
Kalgaonkar, Swati;Lonnerdal, Bo
Ferritin (Ft) is a large iron-binding protein (~450 kDa) that is found in plant and animal cells and can sequester up to 4,500 iron (Fe) atoms per Ft molecule. Our previous studies on intestinal Caco-2 cells have shown that dietary factors affect the uptake of Fe from ferritin in a manner different from that of Fe from FeSO4, suggesting a different mechanism for cellular uptake. The objective of this study was to determine the mechanism for Ft-Fe uptake using Caco-2 cells. Binding of 59Fe-labeled Ft at 4° C showed saturable kinetics and Scatchard analysis resulted in a KD of 1.6 μM, strongly indicating a receptor-mediated process. Competitive binding studies with excess unlabelled Ft significantly reduced binding and uptake studies at 37° C showed saturation after 4 h. Enhancing and blocking endocytosis using Mas-7 (a G-protein activator) and hypertonic medium (0.5 M sucrose), respectively, demonstrated that Ft-Fe uptake by Mas-7 treated cells was 140% of control cells, whereas sucrose treatment resulted in a statistically significant reduction in Ft-Fe uptake by 70% as compared to controls. Inhibition of macropinocytosis with 5-(N,N-dimethyl)-amiloride (Na+/H+ antiport blocker) resulted in a decrease (by ~20%) in Ft-Fe uptake at high concentrations of Ft, suggesting that enterocytes can use more than one Ft-uptake mechanism in a concentration dependent manner. These results suggest that Ft uptake by enterocytes is carried out via endocytosis when Ft levels are within a physiological range, whereas Ft at higher concentrations may be absorbed using the additional mechanism of macropinocytosis.
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影响因子：
13.5
作者：
ADAMS, PC;CHAU, LA
通讯作者：
CHAU, LA
影响因子：
6.1
作者：
Glahn, RP;Wortley, GM;Miller, DD
通讯作者：
Miller, DD
DOI：
10.1152/ajpgi.00443.2001
发表时间：
2002-11-01
影响因子：
4.5
作者：
Follett, JR;Suzuki, YA;Lönnderdal, B
通讯作者：
Lönnderdal, B
影响因子：
7.1
作者：
LYNCH, SR;BEARD, JL;COOK, JD
通讯作者：
COOK, JD
影响因子：
5.6
作者：
Kalgaonkar, Swati;Loennerdal, Bo
通讯作者：
Loennerdal, Bo