Small molecule-mediated refolding and activation of myosin motor function.
Small molecule-mediated refolding and activation of myosin motor function.
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DOI：
10.7554/elife.01603
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发表时间：
2014-02-11
期刊：
影响因子：
7.7
通讯作者：
Manstein DJ
中科院分区：
文献类型：
--
作者：
Radke MB;Taft MH;Stapel B;Hilfiker-Kleiner D;Preller M;Manstein DJ
小分子EMD 57033已显示刺激肌动球蛋白ATP酶活性和肌丝的收缩性。在这里，我们表明，EMD 57033绑定到一个变构口袋中的肌球蛋白运动域。EMD 57033结合保护肌球蛋白对抗热应激和热变性。在EMD 57033的存在下，ATP水解，肌动蛋白和核苷酸结合位点之间的偶联，以及在ATP存在下的肌动蛋白亲和力增加超过10倍。将EMD 57033添加到热灭活的β-心肌肌球蛋白中，然后再折叠和再激活ATP酶和运动活性。在热应激的心肌细胞中，应激标志物心房利钠肽的表达被EMD 57033抑制。因此，EMD 57033显示出比以前与小的药物样化合物相关的活性谱更宽的活性谱。介导重折叠和增强酶功能的变构效应物具有改善心力衰竭、肌病和蛋白质错误折叠疾病的治疗的潜力。http://dx.doi.org/10.7554/eLife.01603.001我们的肌肉含有大量的“运动蛋白”，称为肌球蛋白。为了收缩肌肉，许多肌球蛋白分子消耗能量沿着由另一种分子（称为肌动蛋白）组成的细丝“行走”，并产生拉力。像其他蛋白质一样，肌球蛋白必须折叠成正确的形状才能发挥作用，但高温或其他类型的压力会破坏它们采用或保持正确形状的能力。例如，肌球蛋白的错误折叠可能导致肌肉疾病，包括影响心脏的疾病;因此，人们正在努力寻找可以稳定蛋白质折叠并治疗这些疾病的化合物。小分子EMD 57033是在20多年前发现的，其增加肌肉收缩强度的能力表明它可用于治疗慢性心力衰竭，但副作用的风险限制了其临床应用。改善心肌功能的其他化合物的有效性仍然常规地与EMD 57033进行比较，但是负责其对肌肉组织作用的确切机制仍然未知。现在，Radke、塔夫脱等人已经确定了EMD 57033所结合的肌球蛋白的一部分，并展示了这是如何激活肌肉收缩的。实验还出乎意料地揭示了EMD 57033能够将错误折叠的肌球蛋白转化回完全功能的形式。通过揭示这种重折叠效应，Radtke，塔夫脱等人的发现表明，类似的小分子可用作治疗蛋白质错误折叠疾病、肌肉疾病和心力衰竭的药物。DOI：http://dx.doi.org/10.7554/eLife.01603.002网站
The small molecule EMD 57033 has been shown to stimulate the actomyosin ATPase activity and contractility of myofilaments. Here, we show that EMD 57033 binds to an allosteric pocket in the myosin motor domain. EMD 57033-binding protects myosin against heat stress and thermal denaturation. In the presence of EMD 57033, ATP hydrolysis, coupling between actin and nucleotide binding sites, and actin affinity in the presence of ATP are increased more than 10-fold. Addition of EMD 57033 to heat-inactivated β-cardiac myosin is followed by refolding and reactivation of ATPase and motile activities. In heat-stressed cardiomyocytes expression of the stress-marker atrial natriuretic peptide is suppressed by EMD 57033. Thus, EMD 57033 displays a much wider spectrum of activities than those previously associated with small, drug-like compounds. Allosteric effectors that mediate refolding and enhance enzymatic function have the potential to improve the treatment of heart failure, myopathies, and protein misfolding diseases. DOI: http://dx.doi.org/10.7554/eLife.01603.001 Our muscles contain large numbers of ‘motor proteins’ called myosins. To contract a muscle, many myosin molecules expend energy to ‘walk’ along a filament made from another molecule, called actin, and generate a pulling force. Like other proteins, myosins must fold into the correct shape to work, but high temperatures or other types of stress can disrupt their ability to adopt or maintain the correct shape. Misfolding of myosins, for example, can result in muscular diseases, including those that affect the heart; so there is an ongoing effort to find compounds that can stabilize protein folding and treat these diseases. The small molecule EMD 57033 was discovered over 20 years ago, and its ability to increase the strength of muscle contractions suggested that it could be used to treat chronic heart failure, but the risk of side effects limited its clinical use. The effectiveness of other compounds that improve cardiac muscle function is still routinely compared to EMD 57033, however the exact mechanism responsible for its effect on muscle tissue remained unknown. Now Radke, Taft et al. have identified the part of the myosin protein that EMD 57033 binds to, and shown how this activates muscle contraction. The experiments also, unexpectedly, revealed that EMD 57033 is able to convert misfolded myosin back into the fully functional form. By revealing this refolding effect, the findings of Radtke, Taft et al. suggest that similar small molecules could be used as drugs for the treatment of protein misfolding diseases, muscular diseases, and heart failure. DOI: http://dx.doi.org/10.7554/eLife.01603.002