Stolz M, Stoffler D, Aebi U, Goldsbury C
M. E. Müller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
J Struct Biol. 2000 Sep;131(3):171-80. doi: 10.1006/jsbi.2000.4301.
The atomic force microscope (AFM) is a unique imaging tool that enables the tracking of single macromolecule events in response to physiological effectors and pharmacological stimuli. Direct correlation can therefore be made between structural and functional states of individual biomolecules in an aqueous environment. This review explores how time-lapse AFM has been used to learn more about normal and disease-associated biological processes. Three specific examples have been chosen to illustrate the capabilities of this technique. In the cell, actin polymerizes into filaments, depolymerizes, and undergoes interactions with numerous effector molecules (i.e., severing, capping, depolymerizing, bundling, and cross-linking proteins) in response to many different stimuli. Such events are critical for the function and maintenance of the molecular machinery of muscle contraction and the dynamic organization of the cytoskeleton. One goal is to use time-lapse AFM to examine and manipulate some of these events in vitro, in order to learn more about how these processes occur in the cell. Aberrant protein polymerization into amyloid fibrils occurs in a multitude of diseases, including Alzheimer's and type 2 diabetes. Local amyloid deposits may cause organ dysfunction and cell death; hence, it is of interest to learn how to interfere with fibril formation. One application of time-lapse AFM in this area has been the direct visualization of amyloid fibril growth in vitro. This experimental approach holds promise for the future testing of potential therapeutic drugs, for example, by directly visualizing at which level of fibril assembly (i.e., nucleation, elongation, branching, or lateral association of protofibrils) a given active compound will interfere. Nuclear pore complexes (NPCs) are large supramolecular assemblies embedded in the nuclear envelope. Transport of ions, small molecules, proteins, RNAs, and RNP particles in and out of the nucleus occurs via NPCs. Time-lapse AFM has been used to structurally visualize the response of individual NPC particles to various chemical and physical effectors known to interfere with nucleocytoplasmic transport. Taken together, such time-lapse AFM studies could provide novel insights into the molecular mechanisms of fundamental biological processes under both normal and pathological conditions at the single molecule level.
原子力显微镜（AFM）是一种独特的成像工具，能够追踪单个大分子对生理效应物和药理刺激的响应事件。因此，可以在水性环境中直接关联单个生物分子的结构和功能状态。本综述探讨了延时原子力显微镜如何用于更深入了解正常和疾病相关的生物过程。选择了三个具体例子来说明该技术的能力。在细胞中，肌动蛋白聚合成细丝，解聚，并响应许多不同刺激与众多效应分子相互作用（即切断、封端、解聚、成束和交联蛋白）。这些事件对于肌肉收缩分子机制的功能和维持以及细胞骨架的动态组织至关重要。一个目标是使用延时原子力显微镜在体外检查和操纵其中一些事件，以便更多地了解这些过程在细胞中是如何发生的。异常蛋白质聚合成淀粉样原纤维发生在多种疾病中，包括阿尔茨海默病和2型糖尿病。局部淀粉样沉积物可能导致器官功能障碍和细胞死亡；因此，了解如何干扰原纤维形成很有意义。延时原子力显微镜在这一领域的一个应用是在体外直接观察淀粉样原纤维的生长。这种实验方法有望用于未来潜在治疗药物的测试，例如，通过直接观察给定活性化合物将在原纤维组装的哪个水平（即原纤维的成核、伸长、分支或横向缔合）产生干扰。核孔复合体（NPC）是嵌入核膜的大型超分子组装体。离子、小分子、蛋白质、RNA和RNP颗粒进出细胞核的运输通过核孔复合体进行。延时原子力显微镜已用于在结构上观察单个核孔复合体颗粒对已知干扰核质运输的各种化学和物理效应物的响应。综上所述，此类延时原子力显微镜研究可以在单分子水平上为正常和病理条件下基本生物过程的分子机制提供新的见解。
