Graumann Peter L, Defeu Soufo Hervé Joël
Biochemie, Fachbereich Chemie, Philipps-Universität Marburg, Germany.
Bioessays. 2004 Nov;26(11):1209-16. doi: 10.1002/bies.20126.
Actin performs structural as well as motor-like functions in eukaryotic cells. Orthologues of actin have also been identified in bacteria, where they perform an essential function during cell growth. Bacterial actins are implicated in the maintenance of rod-shaped cell morphology, and appear to form a cytoskeletal structure, localising as helical filaments underneath the cell membrane. Recently, a plasmid-borne actin orthologue has been shown to perform a mitotic-like function during segregation of a plasmid, and chromosomally encoded actin proteins were found to play an important role in chromosome segregation. Based on the findings that actin filaments are dynamic structures in two bacterial species, we propose that actins perform motor functions rather than a purely structural role in bacteria. We suggest that an intracellular motor exists in bacteria that could be derived from an ancestral actin motor that was present in cells early in evolution.
肌动蛋白在真核细胞中执行结构以及类似运动的功能。在细菌中也鉴定出了肌动蛋白的直系同源物，它们在细胞生长过程中发挥着重要作用。细菌肌动蛋白与维持杆状细胞形态有关，并且似乎形成一种细胞骨架结构，定位在细胞膜下方呈螺旋状细丝。最近，一种质粒携带的肌动蛋白直系同源物已被证明在质粒分离过程中执行类似有丝分裂的功能，并且发现染色体编码的肌动蛋白蛋白在染色体分离中起重要作用。基于肌动蛋白丝在两种细菌物种中是动态结构这一发现，我们提出肌动蛋白在细菌中执行运动功能而非纯粹的结构作用。我们认为细菌中存在一种细胞内运动蛋白，它可能源自进化早期细胞中存在的一种原始肌动蛋白运动蛋白。
