Uncoupling store-operated Ca2+ entry and altered Ca2+ release from sarcoplasmic reticulum through silencing of junctophilin genes
Uncoupling store-operated Ca2+ entry and altered Ca2+ release from sarcoplasmic reticulum through silencing of junctophilin genes
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DOI：
10.1529/biophysj.105.076570
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发表时间：
2006-06-01
影响因子：
3.4
通讯作者：
Pan, Zui
中科院分区：
文献类型：
--
作者：
Hirata, Yutaka;Brotto, Marco;Pan, Zui
Junctophilin (JP) 介导肌肉细胞中细胞表面和细胞内膜之间的紧密接触，确保有效的兴奋-收缩耦合。在这里，我们证明，通过减少 JP 表达，破坏质膜横向管状 (TT) 内陷和肌浆网 (SR) 终池形成的三联结结构，导致肌肉细胞中 Ca2+ 稳态缺陷。使用针对 JP1 和 JP2 基因的小发夹干扰 RNA (shRNA) 的腺病毒，我们可以实现骨骼肌数量中 JP 的急性抑制。经过 shRNA 处理的肌肉表现出变形的三联体连接和钙池操纵的 Ca2+ 进入 (SOCE) 减少，这可能是由于从 SR 到 TT 的解耦逆行信号传导所致。 JP 的敲除还会导致 SR Ca2+ 储存减少并改变咖啡因诱导的 Ca2+ 释放，表明 TT 膜对 SR Ca2+ 释放机制的顺行调节。我们的数据表明，JP 在控制肌肉细胞的整体细胞内 Ca2+ 稳态中发挥着重要作用。我们推测 JP 表达的改变可能是与某些肌肉疾病和衰老相关的一些表型变化的基础。
Junctophilin ( JP) mediates the close contact between cell surface and intracellular membranes in muscle cells ensuring effcient excitation-contraction coupling. Here we demonstrate that disruption of triad junction structure formed by the transverse tubular (TT) invagination of plasma membrane and terminal cisternae of sarcoplasmic reticulum (SR) by reduction of JP expression leads to defective Ca2+ homeostasis in muscle cells. Using adenovirus with small hairpin interference RNA (shRNA) against both JP1 and JP2 genes, we could achieve acute suppression of JPs in skeletal muscle numbers. The shRNA-treated muscles exhibit deformed triad junctions and reduced store-operated Ca2+ entry (SOCE), which is likely due to uncoupled retrograde signaling from SR to TT. Knockdown of JP also causes a reduction in SR Ca2+ storage and altered caffeine-induced Ca2+ release, suggesting an orthograde regulation of the TT membrane on the SR Ca2+ release machinery. Our data demonstrate that JPs play an important role in controlling overall intracellular Ca2+ homeostasis in muscle cells. We speculate that altered expression of JPs may underlie some of the phenotypic changes associated with certain muscle diseases and aging.