Pichoff Sebastien, Lutkenhaus Joe
Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
Mol Microbiol. 2005 Mar;55(6):1722-34. doi: 10.1111/j.1365-2958.2005.04522.x.
The cytokinetic Z ring is required for bacterial cell division. It consists of polymers of FtsZ, the bacterial ancestor of eukaryotic tubulin, linked to the cytoplasmic membrane. Formation of a Z ring in Escherichia coli occurs as long as one of two proteins, ZipA or FtsA, is present. Both of these proteins bind FtsZ suggesting that they might function to tether FtsZ filaments to the membrane. Although ZipA has a transmembrane domain and therefore can function as a membrane anchor, interaction of FtsA with the membrane has not been explored. In this study we demonstrate that FtsA, which is structurally related to eukaryotic actin, has a conserved C-terminal amphipathic helix that is essential for FtsA function. It is required to target FtsA to the membrane and subsequently to the Z ring. As FtsA is much more widely conserved in bacteria than ZipA, it is likely that FtsA serves as the principal membrane anchor for the Z ring.
细胞动力学Z环是细菌细胞分裂所必需的。它由FtsZ聚合物组成，FtsZ是真核微管蛋白的细菌祖先，与细胞质膜相连。只要ZipA或FtsA这两种蛋白质中的一种存在，大肠杆菌中就会形成Z环。这两种蛋白质都与FtsZ结合，表明它们可能起到将FtsZ细丝拴系到膜上的作用。虽然ZipA有一个跨膜结构域，因此可以作为膜锚发挥作用，但FtsA与膜的相互作用尚未得到研究。在本研究中，我们证明，与真核肌动蛋白结构相关的FtsA有一个保守的C末端两亲螺旋，这对FtsA的功能至关重要。它需要将FtsA靶向到膜上，随后靶向到Z环。由于FtsA在细菌中的保守程度比ZipA广泛得多，FtsA很可能作为Z环的主要膜锚。
