期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:2004
卷号:101
期号:45
页码:15921-15926
DOI:10.1073/pnas.0404200101
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:The bacterium Caulobacter crescentus divides asymmetrically as part of its normal life cycle. This asymmetry is regulated in part by the membrane-bound histidine kinase PleC, which localizes to one pole of the cell at specific times in the cell cycle. Here, we track single copies of PleC labeled with enhanced yellow fluorescent protein (EYFP) in the membrane of live Caulobacter cells over a time scale of seconds. In addition to the expected molecules immobilized at one cell pole, we observed molecules moving throughout the cell membrane. By tracking the positions of these molecules for several seconds, we determined a diffusion coefficient (D) of 12 {+/-} 2 x 10-3 {micro}m2/s for the mobile copies of PleC not bound at the cell pole. This D value is maintained across all cell cycle stages. We observe a reduced D at poles containing localized PleC-EYFP; otherwise D is independent of the position of the diffusing molecule within the bacterium. We did not detect any directional bias in the motion of the PleC-EYFP molecules, implying that the molecules are not being actively transported.