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The effects of brefeldin A and monensin on ferritin secretion in Aedes aegypti larval cells
Author(s) -
Shen MengChieh,
Mayo Jonathan J.,
Geiser Dawn L.,
J. Winzerling Joy
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a98-b
Subject(s) - ferritin , brefeldin a , golgi apparatus , hemolymph , secretion , aedes aegypti , biology , transferrin , microbiology and biotechnology , biochemistry , cytoplasm , transferrin receptor , chemistry , larva , endoplasmic reticulum , botany
In mammals, iron can be taken up by somatic cells as ferric‐transferrin by transferrin receptor‐mediated endocytosis. Iron can be stored in ferritin or incorporated into proteins. Mammalian ferritin is a multimer of 24 subunits of heavy and light chains and is found primarily in cytoplasm and rarely in circulation. Unlike mammals, the majority of insects have ferritin in the hemolymph. In Diptera, holoferritin is found in the secretory pathway. These findings suggest that insect ferritin could be involved in iron movement in the animal. Mosquito (Diptera) ferritin also occurs in hemolymph and the messages for the heavy and light chain subunits contain secretion signal sequences indicating these subunits are targeted to the secretory pathway. We found that A. aegypti larval cells (CCL‐125) exposed to iron as ferric ammonium citrate (FAC) increased secreted ferritin in a dose‐dependent manner. In time course experiments, we showed increased ferritin in culture medium at 9 hours following treatment with 100μM FAC. We also found that ferritin co‐localized with the Golgi apparatus during iron deprivation; following iron treatment larval cells showed increased cytoplasmic and vesicular ferritin. To study the secretory pathway of ferritin, we treated CCL‐125 cells with 6 μg/ml of Brefeldin A (BFA). These preliminary experiments showed that BFA did not decrease the secretion of ferritin into the culture medium in response to iron. In this study, we applied another Golgi disrupting agent, monensin, as well as BFA (8 μg/ml) to see the effects on ferritin secretion. Research was funded by NIH (GM056812).