α-Actinin/titin interaction: A dynamic and mechanically stable cluster of bonds in the muscle Z-disk
α-Actinin/titin interaction: A dynamic and mechanically stable cluster of bonds in the muscle Z-disk
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DOI：
10.1073/pnas.1612681114
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发表时间：
2017-01-31
影响因子：
11.1
通讯作者：
Rief, Matthias
中科院分区：
文献类型：
--
作者：
Grison, Marco;Merkel, Ulrich;Rief, Matthias
肌联蛋白在肌肉Z盘中的稳定锚定对于在被动拉伸期间保持肌肉完整性至关重要。用于将肌联蛋白锚定在Z盘中的主要候选者之一是肌动蛋白交联剂α-辅肌动蛋白。α-辅肌动蛋白的钙调素样结构域结合肌联蛋白的Z-重复序列。然而，这一重要相互作用的力学和动力学性质仍然是未知的。在这里，我们使用双光束光镊分析研究这种相互作用的机制在单分子水平。一个单一的相互作用α-辅肌动蛋白和肌联蛋白原来是令人惊讶的弱，如果施加的力量。根据施力方向的不同，松解力可以增加三倍以上。我们的研究结果表明，多个α-辅肌动蛋白/Z-重复相互作用的合作，以确保长期稳定的肌联蛋白锚定，同时允许各个组件动态交换的模型。
Stable anchoring of titin within the muscle Z-disk is essential for preserving muscle integrity during passive stretching. One of the main candidates for anchoring titin in the Z-disk is the actin crosslinker a-actinin. The calmodulin-like domain of alpha-actinin binds to the Z-repeats of titin. However, the mechanical and kinetic properties of this important interaction are still unknown. Here, we use a dual-beam optical tweezers assay to study the mechanics of this interaction at the single-molecule level. A single interaction of alpha-actinin and titin turns out to be surprisingly weak if force is applied. Depending on the direction of force application, the unbinding forces can more than triple. Our results suggest a model where multiple alpha-actinin/Z-repeat interactions cooperate to ensure long-term stable titin anchoring while allowing the individual components to exchange dynamically.