The structure of Ca(2+) release units in arthropod body muscle indicates an indirect mechanism for excitation-contraction coupling.
The structure of Ca(2+) release units in arthropod body muscle indicates an indirect mechanism for excitation-contraction coupling.
复制标题
节肢动物体肌肉中Ca(2)释放单元的结构表明了兴奋-收缩耦合的间接机制。
DOI：
10.1016/s0006-3495(02)75284-3
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发表时间：
2002
影响因子：
3.4
通讯作者：
Franzini-Armstrong,Clara
中科院分区：
文献类型：
--
作者：
Takekura,Hiroaki;Franzini-Armstrong,Clara
本文研究了三种节肢动物体肌Ryanodine受体（RyRs）和L型钙通道的相对分布。在所有肌肉中，并置SR和T小管元件之间的连接间隙中的兰尼碱受体的分布是高度有序的。相比之下，T小管的连接膜被独特的大颗粒占据，这些大颗粒聚集在小的连接区域内，但它们的排列没有顺序。我们建议，连接T小管的大颗粒代表参与兴奋-收缩（e-c）耦合的L-型Ca 2+通道，基于它们的大小和位置与骨骼肌和心肌的L-型Ca 2+通道或二氢吡啶受体（DHPR）的相似性。DHPRs在节肢动物体肌肉中的随机排列表明它们与RyRs之间没有密切的联系。这与脊椎动物心肌的结构相匹配，并且与心脏和无脊椎动物横纹肌中e-c偶联机制的相似性保持一致。
The relative disposition of ryanodine receptors (RyRs) and L-type Ca2+channels was examined in body muscles from three arthropods. In all muscles the disposition of ryanodine receptors in the junctional gap between apposed SR and T tubule elements is highly ordered. By contrast, the junctional membrane of the T tubule is occupied by distinctive large particles that are clustered within the small junctional domain, but show no order in their arrangement. We propose that the large particles of the junctional T tubules represent L-type Ca2+channels involved in excitation-contraction (e-c) coupling, based on their similarity in size and location with the L-type Ca2+channels or dihydropyridine receptors (DHPRs) of skeletal and cardiac muscle. The random arrangement of DHPRs in arthropod body muscles indicates that there is no close link between them and RyRs. This matches the architecture of vertebrate cardiac muscle and is in keeping with the similarity in e-c coupling mechanisms in cardiac and invertebrate striated muscles.