Junctin and calsequestrin overexpression in cardiac muscle: the role of junctin and the synthetic and delivery pathways for the two proteins.
Junctin and calsequestrin overexpression in cardiac muscle: the role of junctin and the synthetic and delivery pathways for the two proteins.
复制标题
心肌中的连接蛋白和钙结合蛋白过度表达：连接蛋白的作用以及这两种蛋白质的合成和递送途径。
DOI：
10.1016/s0022-2828(03)00181-0
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发表时间：
2003
影响因子：
5
通讯作者：
Franzini-Armstrong,Clara
中科院分区：
文献类型：
--
作者：
Tijskens,Pierre;Jones,LarryR;Franzini-Armstrong,Clara
肌细胞中的Ca2+储存和释放由连接肌浆网（jSR）蛋白的复合物控制，其包括钙结合蛋白钙螯合蛋白（CSQ）、Ca2+释放通道（Ryanodine受体或RyR）和结合RyR的两个跨膜蛋白：连接蛋白（JNC）和三聚体蛋白（Tr）。在CSQ和JNC联合过表达的转基因小鼠中研究了CSQ和JNC之间的关系及其对jSR囊泡结构的贡献。我们发现，CSQ，就其本身而言，有一个弥漫性的配置在肌浆网（SR）腔。JNC的过表达导致CSQ在SR膜附近更紧密地堆积，推测是由于CSQ通过JNC与膜结合。在过度表达以及在正常分化的心肌中的结构变化的定量和定性分析说明了CSQ和JNC的靶向和递送到分化的心肌细胞的jSR的合成途径和事件。CSQ从高尔基体传递到SR，在那里它出芽成为jSR囊泡的前体。JNC直接到达jSR囊泡，但其到达相对于CSQ延迟。
Ca2+storage and release in muscle cells are controlled by a complex of junctional sarcoplasmic reticulum (jSR) proteins, that includes the calcium-binding protein calsequestrin (CSQ), the Ca2+-release channel (ryanodine receptor or RyR) and two transmembrane proteins that bind to RyR: junctin (JNC) and triadin (Tr). The relationship between CSQ and JNC, and their contributions to the architecture of the jSR vesicle was studied in transgenic mice with combined overexpression of CSQ and JNC. We find that CSQ, on its own, has a diffuse disposition in the sarcoplasmic reticulum (SR) lumen. Overexpression of JNC results in a tighter packing of CSQ in proximity of the SR membrane, presumably due to the binding of CSQ to the membrane by JNC. Quantitative and qualitative analysis of structural changes in the overexpressing as well as in the normally differentiating myocardium illustrate the synthetic pathways and the events in the targeting and delivery of CSQ and JNC to the jSR of the differentiating cardiac myocyte. CSQ is delivered from the Golgi to the SR, where it buds out into precursors of the jSR vesicles. JNC reaches the jSR vesicles directly, but its arrival is delayed relative to CSQ.