Acidic NAADP-releasable Ca2+ compartments in the megakaryoblastic cell line MEG01
Acidic NAADP-releasable Ca2+ compartments in the megakaryoblastic cell line MEG01
复制标题
DOI：
10.1016/j.bbamcr.2011.05.005
复制
发表时间：
2011-08-01
影响因子：
5.1
通讯作者：
Rosado, Juan A.
中科院分区：
文献类型：
--
作者：
Dionisio, Natalia;Albarran, Letizia;Rosado, Juan A.
背景资料：双孔通道（two-pore channels，TPC）是一类新型的细胞内钙释放通道，是最有效的细胞内钙动员信使NAADP（nicotinic acid adenine dinucleotide phosphate）的受体。目的：研究NAADP介导的巨核细胞系MEG 01胞内钙释放。方法：采用荧光法分别用fura-2和fura-1f记录胞浆和胞腔内游离钙浓度的变化。结果：用H+/K+离子载体尼日利亚菌素或V型H+-ATP酶选择性抑制剂巴弗洛霉素A1处理MEG 01细胞，发现MEG 01细胞内存在酸性钙库，对SERCA抑制剂2，5-二-（叔丁基）-1，4-氢醌（TBHQ）敏感。NAADP从MEG 01细胞中的酸性溶酶体样Ca 2+储存中释放Ca 2+，可能是由TPC 1和TPC 2的激活介导的，如TPC 1和TPC 2表达沉默和过表达所证明的。Ca 2+流出的酸性溶酶体样的Ca 2+存储或内质网（ER）的结果在ryanodine敏感激活的Ca 2+诱导的Ca 2+释放（CICR）从互补Ca 2 + compartment.Conclusion：我们的研究结果表明，第一次NAADP诱发的Ca 2+释放从酸性车厢通过激活的TPC 1和TPC 2，和CICR，在巨核细胞系。(C)2011爱思唯尔有限公司版权所有。
Background: A novel family of intracellular Ca2+-release channels termed two-pore channels (TPCs) has been presented as the receptors of NAADP (nicotinic acid adenine dinucleotide phosphate), the most potent Ca2+ mobilizing intracellular messenger. TPCs have been shown to be exclusively localized to the endolysosomal system mediating NAADP-evoked Ca2+ release from the acidic compartments.Objectives: The present study is aimed to investigate NAADP-mediated Ca2+ release from intracellular stores in the megakaryoblastic cell line MEG01.Methods: Changes in cytosolic and intraluminal free Ca2+ concentrations were registered by fluorimetry using fura-2 and fura-if, respectively: TPC expression was detected by PCR.Results: Treatment of MEG01 cells with the H+/K+ ionophore nigericin or the V-type H+-ATPase selective inhibitor bafilomycin A1 revealed the presence of acidic Ca2+ stores in these cells, sensitive to the SERCA inhibitor 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ). NAADP releases Ca2+ from acidic lysosomal-like Ca2+ stores in MEG01 cells probably mediated by the activation of TPC1 and TPC2 as demonstrated by TPC1 and TPC2 expression silencing and overexpression. Ca2+ efflux from the acidic lysosomal-like Ca2+ stores or the endoplasmic reticulum (ER) results in ryanodine-sensitive activation of Ca2+-induced Ca2+ release (CICR) from the complementary Ca2+ compartment.Conclusion: Our results show for the first time NAADP-evoked Ca2+ release from acidic compartments through the activation of TPC1 and TPC2, and CICR, in a megakaryoblastic cell line. (C) 2011 Elsevier B.V. All rights reserved.