Dynamic Events in Myosin and Actin and Their Function

细胞运动和力的产生是生物体的基本特征。肌动蛋白，最多的 真核细胞中保守和丰富的蛋白质在这些过程中起着关键作用。长期的 这项研究的目的是详细了解作用力背后的结构和动态事件 肌动球蛋白的生成和肌动蛋白细丝的重塑以满足细胞的需要。我们将努力实现这一目标 通过结合x射线结构测定肌动蛋白低聚体及其络合物，以及溶液 研究通过交联、动力学、相互作用和功能来探测肌动蛋白细丝的结构、动力学、相互作用和功能 光谱、电子显微镜和诱变方法。这三个项目的具体目标是 这项研究是： I，(I-IV)用射线裂解、质谱学、裂解和交联法绘制相互作用部位图 肌动蛋白和粘连蛋白，肌动蛋白和肌球蛋白在强结合和弱结合的复合体中。 Ii.(i-iii)结晶和分解肌动蛋白二聚体、四聚体及其与粘连蛋白的络合物的结构， 明胶蛋白片段、封端蛋白和肌球蛋白头部(S1)。 。(i-iii)稳定早期形式的肌动蛋白细丝，并评估反平行二聚体在 花丝枝条的生长；(Iy)用光谱学和诱变方法测试 肌动蛋白上的DNase I结合环；(V)确定肌动蛋白细丝被cofilin和 明胶蛋白，并阐明肌动蛋白相互作用蛋白Aip1激活cofilin功能。 对肌动蛋白的结构、动力学和相互作用的详细了解将有助于阐明 它在肌肉收缩和细胞过程中的作用，如伤口愈合，癌症转移， 免疫细胞的趋化性和宿主与病原体的相互作用。归根结底，这种理解应该有助于 随着影响肌动蛋白相互作用的药物的发现，治疗干预的发展也被发现。

Cell motility and force generation are fundamental features of living organisms. Actin, one of the most conserved and aboundant proteins in eukaryotic cells, plays a key role in these processes. The long-term goal of this research is to provide detailed understanding of structure and dynamic events that underlie force generation by actomyosin and the remodeling of actin filaments for cellular needs. This goal will be pursued through a combination of x-ray structure determination of actin oligomers and their complexes, and solution studies probing actin filaments structure, dynamics, interactions, and fuction via cross-linking, kinetic, spectroscopic, electron microscopy, and mutagenesis methods. The specific aims of the three projects of this study are: I, (i-iv) To map by radiolysis, mass spectrometry, cleavage, and cross-linking methods the interaction sites of actin and cofilin, and actin and myosin in strongly and weakly bound complexes. II. (i-iii) To crystallize and solve the structures of actin dimers, tetramers, and their complexes with cofilin, gelsolin fragments, capping proteins, and myosin heads (S1). . (i-iii) To stabilize the early forms of actin filaments and assess the role of anti-parallel dimers in the growth of filament branches; (iy) To test by spectroscopic and mutagenesis methods the structure of the DNase I binding loop on actin; (v) To determine the mechanism of actin filament severing by cofilin and gelsolin, and to clarify the activation of cofilin function by the actin interacting protein Aip1. Detailed understanding of the structure, dynamics and interactions of actin should clarify the mechanism of its function in muscle contraction and in cellular processes, such as wound healing, cancer metastasis, chemotaxis of immune cells and host-pathogen interactions. Ultimately, this understanding should help in the development of therapeutic interventions as drugs that influence actin interactions are discovered.