Compartmentalized expression of three novel sarco/endoplasmic reticulum Ca2+ATPase 3 isoforms including the switch to ER stress, SERCA3f, in non-failing and failing human heart
Compartmentalized expression of three novel sarco/endoplasmic reticulum Ca2+ATPase 3 isoforms including the switch to ER stress, SERCA3f, in non-failing and failing human heart
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DOI：
10.1016/j.ceca.2008.08.002
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发表时间：
2009-02-01
期刊：
影响因子：
4
通讯作者：
Enouf, Jocelyne
中科院分区：
文献类型：
--
作者：
Dally, Saoussen;Monceau, Virginie;Enouf, Jocelyne
人肌质/内质网（ER）Ca（2+）ATP酶3（SERCA 3）基因产生SERCA 3a-3f同种型，后者在体外诱导ER应激。在这里，我们首次证明了SERCA 3a，-3d和-3f蛋白在心脏中的共表达。内源性蛋白质的证据是通过使用同种型特异性抗体，包括一种新的SERCA 3d特异性抗体，蛋白质裂解物的蛋白质印迹或膜蛋白的免疫沉淀。左心室组织和分离的心肌细胞的免疫定位研究显示SERCA 3同种型的明显区室化，因为检测到SERCA 3a的均匀分布，同时分别在细胞核周围和质膜附近观察到-3d和-3f同种型。其次，我们研究了它们在衰竭心脏中的表达，包括混合型（MCM）（n = 1）和特发性扩张型（IDCM）心肌病（n = 4）。与对照组（n = 5）相比，所有患者中观察到SERCA 3a和-3d mRNA的相似表达。相比之下，SERCA 3f mRNA在衰竭心脏中被发现上调（125 +/- 7%）。值得注意的是，SERCA 3f的过表达增加了ER应激标志物的表达，包括X-box-binding protein-1（XBP-1）mRNA的加工（176 +/- 24%），以及XBP-1蛋白和葡萄糖调节蛋白（GRP）78的表达（232 +/- 21%）。这些发现重新审视了人类心脏的Ca（2+）ATP酶系统，并表明SERCA 3f可能解释了心力衰竭中体内ER应激的机制。(C)2008爱思唯尔有限公司保留所有权利。
The human sarco/endoplasmic reticulum (ER) Ca(2+)ATPase 3 (SERCA3) gene gives rise to SERCA3a-3f isoforms, the latter inducing ER stress in vitro. Here, we first demonstrated the co-expression of SERCA3a, -3d and -3f proteins in the heart. Evidence for endogenous proteins was obtained by using isoform-specific antibodies including a new SERCA3d-specific antibody, and either Western blotting of protein lysates or immunoprecipitation of membrane proteins. An immunolocalization study of both left ventricle tissue and isolated cardiomyocytes showed a distinct compartmentalization of the SERCA3 isoforms, as a uniform distribution of SERCA3a was detected while -3d and -3f isoforms were observed around the nucleus and in close vicinity of plasma membrane, respectively. Second, we studied their expressions in failing hearts including mixed (MCM) (n = 1) and idiopathic dilated (IDCM) cardiomyopathies (n = 4). Compared with controls (n = 5), similar expressions of SERCA3a and -3d mRNAs were observed in all patients. In contrast, SERCA3f mRNA was found to be up-regulated in failing hearts (125 +/- 7%). Remarkably, overexpression of SERCA3f paralleled an increase in ER stress markers including processing of X-box-binding protein-1 (XBP-1) mRNA (176 +/- 24%), and expression of XBP-1 protein and glucose-regulated protein (GRP)78 (232 +/- 21%).These findings revisit the human heart's Ca(2+)ATPase system and indicate that SERCA3f may account for the mechanism of ER stress in vivo in heart failure. (C) 2008 Elsevier Ltd. All rights reserved.