The expression of Lamin A mutant R321X leads to endoplasmic reticulum stress with aberrant Ca(2+) handling.
The expression of Lamin A mutant R321X leads to endoplasmic reticulum stress with aberrant Ca(2+) handling.
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DOI：
10.1111/jcmm.12926
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发表时间：
2016-11
影响因子：
5.3
通讯作者：
Svelto M
中科院分区：
文献类型：
--
作者：
Carmosino M;Gerbino A;Schena G;Procino G;Miglionico R;Forleo C;Favale S;Svelto M
编码A型核纤层蛋白的纤层蛋白A/C基因（LMNA）突变是扩张型心肌病（DCM）最常见的遗传原因。这项研究的重点是在一个意大利家族的几个成员中发现的LMNA无义突变（R321X），该突变产生截断的蛋白质异构体，该异构体与预后不良的严重心肌病共分离。然而，除了无义介导的信使衰变和可能的单倍不足之外，没有提出其他分子机制来解释DCM。本研究的目的是在细胞水平上进一步了解R321X表达诱导的致病机制。我们通过Western blotting从突变携带者心脏活检的整个裂解液中检测R321X的表达。当在HEK293细胞中表达时，GFP‐（或mCherry‐）‐标记的R321X错定位于内质网（ER），诱导内质网应激反应的PERK‐CHOP轴。值得注意的是，共聚焦显微镜显示突变携带者心脏活检切片中的PERK磷酸化。mCherry‐R321X内质网定位错误也会导致内质网Ca2+处理受损，质膜上Ca2+进入能力降低和核Ca2+动力学异常。此外，R321X自身的表达增加了细胞凋亡率。总之，R321X是迄今为止发现的第一个错误定位到内质网的LMNA突变体，它影响与核功能不严格相关的细胞稳态机制。
Mutations in the Lamin A/C gene (LMNA), which encodes A‐type nuclear Lamins, represent the most frequent genetic cause of dilated cardiomyopathy (DCM). This study is focused on a LMNA nonsense mutation (R321X) identified in several members of an Italian family that produces a truncated protein isoform, which co‐segregates with a severe form of cardiomyopathy with poor prognosis. However, no molecular mechanisms other than nonsense mediated decay of the messenger and possible haploinsufficiency were proposed to explain DCM. Aim of this study was to gain more insights into the disease‐causing mechanisms induced by the expression of R321X at cellular level. We detected the expression of R321X by Western blotting from whole lysate of a mutation carrier heart biopsy. When expressed in HEK293 cells, GFP‐ (or mCherry)‐tagged R321X mislocalized in the endoplasmic reticulum (ER) inducing the PERK‐CHOP axis of the ER stress response. Of note, confocal microscopy showed phosphorylation of PERK in sections of the mutation carrier heart biopsy. ER mislocalization of mCherry‐R321X also induced impaired ER Ca2+ handling, reduced capacitative Ca2+ entry at the plasma membrane and abnormal nuclear Ca2+ dynamics. In addition, expression of R321X by itself increased the apoptosis rate. In conclusion, R321X is the first LMNA mutant identified to date, which mislocalizes into the ER affecting cellular homeostasis mechanisms not strictly related to nuclear functions.
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DOI：
10.1186/1478-811x-8-31
发表时间：
2010-12-22
期刊：
Cell communication and signaling : CCS
影响因子：
--
作者：
Chaitanya GV;Steven AJ;Babu PP
通讯作者：
Babu PP
影响因子：
7.8
作者：
Gabriel D;Roedl D;Gordon LB;Djabali K
通讯作者：
Djabali K
影响因子：
2.7
作者：
Carmosino, Monica;Gerbino, Andrea;Svelto, Maria
通讯作者：
Svelto, Maria
影响因子：
3.7
作者：
Forleo C;Carmosino M;Resta N;Rampazzo A;Valecce R;Sorrentino S;Iacoviello M;Pisani F;Procino G;Gerbino A;Scardapane A;Simone C;Calore M;Torretta S;Svelto M;Favale S
通讯作者：
Favale S
影响因子：
3.2
作者：
Ikeda, K;Monden, T;Monden, M
通讯作者：
Monden, M