Department of Biological Science, Florida State University, Biology Unit One Building, Room 206, 81 Chieftain Way, Box 3064370, Tallahassee, FL, 32306-4370, USA,
J Muscle Res Cell Motil. 2013 Aug;34(3-4):275-84. doi: 10.1007/s10974-013-9356-7. Epub 2013 Aug 2.
Tropomyosin and troponin have well known Ca(2+)-regulatory functions in the striated muscle sarcomere. In this review, we summarize experimental evidence that tropomyosin and troponin are localized, with as yet unidentified functional roles, in the striated muscle cell nucleus. We also apply bioinformatics approaches that predict localization of some tropomyosin and troponin to the nucleus, and that SUMOylation could be a covalent modification that modulates their nuclear localization and function. Further, we provide examples of cardiomyopathy mutations that alter the predicted likelihood of nuclear localization and SUMOylation of tropomyosin. These observations suggest novel mechanisms by which cardiomyopathy mutations in tropomyosin and troponin might alter not only cardiac contractility but also nuclear function.
原肌球蛋白和肌钙蛋白在横纹肌肌节中具有众所周知的 Ca(2+)调节功能。在这篇综述中，我们总结了实验证据，表明原肌球蛋白和肌钙蛋白定位于横纹肌细胞核中，具有尚未确定的功能作用。我们还应用生物信息学方法预测了一些原肌球蛋白和肌钙蛋白的核定位，并且 SUMO 化可能是一种共价修饰，调节它们的核定位和功能。此外，我们提供了肌球蛋白突变改变原肌球蛋白核定位和 SUMO 化预测可能性的例子。这些观察结果表明，原肌球蛋白和肌钙蛋白中的心肌病突变可能通过改变不仅是心脏收缩性而且是核功能的新型机制来改变。
