REGULATION OF CELL DIVISION

超出空间 提供了 这项研究的长期目标保持不变。我们的目标是确定 参与细菌细胞分裂的机制和潜在的空间和时间调节 机制等我们的努力集中在FtsZ蛋白，它组装成一个细胞骨架环， 招募其他蛋白质到分裂位点。FtsZ是真核微管蛋白的祖先同源物， 在细胞周期中经历动态组装。它是几种内源性抑制剂的靶点， 作为正常细胞周期的一部分或响应DNA损伤参与细胞分裂的调节。 我们最近的工作表明，苏拉和MinC是FtsZ组装的抑制剂，然而，它们的功能相当 不同.苏拉在DNA损伤后合成，并螯合FtsZ，防止其组装。在 相比之下，MinC是复杂的空间调节系统的一部分，在细胞两极之间振荡 以防止FtsZ聚集在电池极附近。在体外，MinC可以阻止FtsZ组装，并通过 使FtsZ纤维不稳定。体内MinC需要MinD成为功能性抑制剂。MinD激活MinC， 将其募集到膜上并赋予其对隔膜成分的高亲和力。我们的研究 证明MinD通过C-末端两亲性螺旋与膜结合。我们还 表明MinE可以从MinCD囊泡复合物中置换MinC并刺激MinD ATP酶 从囊泡中释放出心智D我们还表明，MinD可以抑制囊泡， tuguo。我们的研究还确定了MinC上参与与MinD结合的位点， 到隔膜。在本建议中，我们将使用遗传和生物化学方法来进一步确定 Min蛋白之间以及Min蛋白与FtsZ之间的相互作用， 细胞分裂我们还将利用从我们的E研究中获得的知识。线圈Min系统探讨 最小系统距B。枯草芽孢杆菌和Par蛋白。

EXCEED THE SPACE PROVIDED. The long term objectives of this research remain unchanged. The goals are to determine the molecular mechanisms involved in bacterial cell division and the underlying spatial and temporal regulatory mechanisms. Our efforts have focused on the FtsZ protein which assembles into a cytoskeletal ring that recruits other proteins to the division site. FtsZ is the ancestral homologue of eukaryotic tubulins and undergoes dynamic assembly during the cell cycle. It is the target of several endogenous inhibitors that participate in the regulation of cell division as part of the normal cell cycle or in response to DNA damage. Our recent work has shown that SulA and MinC are inhibitors of FtsZ assembly, however, they function quite differently. SulA is synthesized following DNA damage and sequesters FtsZ preventing it from assembling. In contrast, MinC is part of a sophisticated spatial regulatory system that oscillates between the poles of the cell to prevent FtsZ from assembling near the cell poles. In vitro, MinC can prevent FtsZ assembly and acts by destabilizing FtsZ filaments. In vivo MinC requires MinD to be a functional inhibitor. MinD activates MinC by recruiting it to the membrane and conferring upon it a high affinity for a septal component. Our studies have demonstrated that MinD binds to the membrane through a C-terminal amphipathic helix. We have also shown that MinE can displace MinC from a MinCD vesicle complex and stimulate the MinD ATPase releasing MinD from the vesicle. We have also shown that MinD can polymerize on vesicles causing tubulation. Our studies have also defined the sites on MinC involved in its binding to MinD and in its binding to the septum. In the present proposal we will use genetic and biochemical approaches to further define the interactions among the Min proteins and between the Min proteins and FtsZ that are necessary to regulate cell division. We will also use the knowledge gained from our study of the E. coil Min system to explore the Min system from B. subtilis and a Par protein.