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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/32402

Title: Orai1–STIM1 formed store-operated Ca2+ channels (SOCs) as the molecular components needed for Pb2+ entry in living cells
Authors: Yu-Fen Chang;Hsiao-Chuan Teng;Sha-Yen Cheng;Chin-Tien Wang;Shi-Hwa Chiou;Lung-Sen Kao;Fu-Jen Kao;Arthur Chiou;De-Ming Yang
Contributors: NTOU:Department of Environmental Biology and Fisheries Science
Keywords: Pb2+;Indo-1;Store-operated Ca2+ channels;Orai1;STIM1;PC12 cells;HeLa cells
Date: 2008-03-15
Issue Date: 2012-06-18T05:42:39Z
Publisher: Toxicology and Applied Pharmacology
Abstract: abstract:Heavy metal lead (Pb2+) is a pollutant and causes severe toxicity when present in human tissues especially the nervous system. Recent reviews have suggested that Pb2+ can target Ca2+-related proteins within neurons and that Ca2+ channels might be a candidate for Pb2+ entry. This study's main aim was to identify the functional entry pathway of Pb2+ into living cells. We firstly characterized the endogenous expression of Orai1 and STIM1 mRNA together with the level of thapsigargin (TG) stimulated capacitative Ca2+ entry in PC12 and HeLa cells; this was done by RT–PCR and time-lapse Ca2+ imaging microscopy, respectively. Our data supported Orai1 and STIM1 as contributing to store-operated Ca2+ channel (SOC) basal activity. Secondly, using the indo-1 quenching method with the SOC blocker 2-APB, we observed that Pb2+ was able to enter cells directly through unactivated SOCs without TG pretreatment. Thirdly, we further demonstrated that co-expression of Orai1 and STIM1 differentially enhanced SOC functional activity (4-fold with PC12 and 5-fold with HeLa cells) and Pb2+ entry (5- to 7-fold with PC12 and 2-fold with HeLa cells). Furthermore, after a 1 h of Pb2+ exposure, the depolarization- and histamine-induced Ca2+ responses were significantly decreased in both PC12 and HeLa cells in a dose-dependent manner. This result indicated that the decreased Ca2+ responses were, in part, due to Pb2+ entry. In summary, our results suggest that SOCs are responsible for Pb2+ permeation and that the Orai1–STIM1 protein complex formed by functional SOCs is one of the molecular components involved in Pb2+ entry.
Relation: 227(3), pp.430–439
URI: http://ntour.ntou.edu.tw/handle/987654321/32402
Appears in Collections:[環境生物與漁業科學學系] 期刊論文

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