Actin is a cytoskeletal protein that is ubiquitous in eukaryotes, hence the corresponding genes and proteins have been isolated from numerous organisms as different as animals, plants, fungi and protozoa. Several atomic models are available for the monomeric as well as the filamentous form, and more than 70 proteins that bind actin and control filament dynamics have been isolated from diverse eukaryotes. Moreover, the function and dynamics of the actin cytoskeleton in several eukaryotic systems have been depicted in depth. Unlike other protozoa, such as amoeba, actin is not an abundant protein in ciliates, whose cytoskeleton is mainly composed of microtubular arrays. Ciliate actin has been studied in several species, and it was established early on that this ciliate protein is very different from that of other eukaryotes. Similarly, the actin-binding proteins studied in ciliates display great differences with those of other eukaryotes. Consequently, ciliate actin has been considered as "unconventional," and this review focuses on molecular data leading to this conclusion.

中文翻译：

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纤毛肌动蛋白的异常特征。

肌动蛋白是真核生物中普遍存在的一种细胞骨架蛋白，因此已经从众多生物中分离出相应的基因和蛋白质，这些生物与动物，植物，真菌和原生动物不同。有几种原子模型可用于单体形式和丝状形式，并且已经从各种真核生物中分离了70多种结合肌动蛋白并控制丝动态的蛋白质。此外，已深入描述了肌动蛋白细胞骨架在几种真核系统中的功能和动力学。不同于变形虫等其他原生动物，肌动蛋白在纤毛虫中不是丰富的蛋白质，纤毛虫的细胞骨架主要由微管阵列组成。纤毛肌动蛋白已经在几个物种中进行了研究，并且早就确定了这种纤毛蛋白与其他真核生物的蛋白有很大不同。同样，在纤毛虫中研究的肌动蛋白结合蛋白与其他真核生物有很大的差异。因此，纤毛肌动蛋白被认为是“非常规的”，而本综述着重于得出该结论的分子数据。