EFFECTS OF MYOSIN BINDING PROTEIN-C ON CARDIAC MYOFILAMENT LATTICE SPACING

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。肌肉的肌丝格子是由粗丝和细丝组成的，在肌肉力量的发展过程中，粗丝和细丝相互滑动。肌球蛋白结合蛋白-C(MyBP-C)的C末端被认为与粗丝蛋白(肌球蛋白和肌动蛋白)强烈结合，因此被认为是物理上增强粗丝的。通过这种方式，MyBP-C促进了沿粗丝的力传递。然而，MyBP-C的N-末端，特别是N-末端的磷酸化位点的结构和功能作用尚不清楚。我们建议用小角X射线衍射法来确定MyBP-C N端的磷酸化位点对肌丝晶格间距的结构影响。我们假设MyBP-C N-末端的磷酸化位点与细丝结合或相互作用。通过这种方式，MyBP-C提供了粗丝和细丝之间的正常间距，并促进了肌丝晶格的规则晶体结构。使用缺失MyBP-C的基因工程小鼠(空模型)，我们先前发现，与存在MyBP-C时(对照模型)相比，缺失MyBP-C时晶格间距相对扩大和混乱。这些数据表明，MyBP-C的N-末端是稳定肌丝晶格所必需的。我们现在有了一个新的小鼠模型，该模型具有突变的MyBP-C，在N-末端没有磷酸化位点(AllPminus-Model)。计划中的X射线实验将显示磷酸化位点是否在稳定粗丝方面起着重要作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The myofilament lattice of muscle is made up of thick and thin filaments, which slide past each other during the development of muscle force. The C-terminus of myosin binding protein-C (MyBP-C) is known to bind strongly to thick filament proteins (myosin and titin) and thereby is assumed to physically reinforce the thick filament. In this way, force transmission along the thick filament is facilitated by MyBP-C. The structural and functional roles of the N-terminus of MyBP-C and in particular the phosphorylation sites at the N-terminus, however, are not clear. We propose to use small angle X-ray diffraction to determine the structural effects of the phosphorylation sites at the N-terminus of MyBP-C on the myofilament lattice spacing. We hypothesize that the phosphorylation sites at the N-terminus of MyBP-C bind to or interact with the thin filament. In this way, MyBP-C provides the normal spacing between the thick and thin filaments and facilitates the regular crystalline structure of the myofilament lattice. Using a genetically engineered mouse missing MyBP-C (Null-model), we have previously found that lattice spacing is relatively expanded and in disarray when MyBP-C is missing compared to that when MyBP-C is present (Control-model). These data imply that the N-terminus of the MyBP-C is required to stabilize the myofilament lattice. We now have a new mouse model possessing mutant MyBP-C void of the phosphorylation sites at the N-terminus (AllPminus-model). The planned x-ray experiments will show whether or not phosphorylation sites are important in stabilizing the thick filament.