Even though their small size and lack of intercellular compartments, bacterial cells are also well organized. As bacteria grow by binary fission, cell division happens at the mid-cell which results in creating a new cell pole. Vibrio cholerae, curved Gram-negative rod that causes cholera, has several key cellular machines found at the old cell pole such as monotrichous flagellum, chemotactic array and the Par apparatus for segregating the larger chromosome (chrI). We previously identified the polar protein which tethers ParA1 chromosome partitioning protein to the cell poles. This protein was dubbed as HubP (hub of the pole), since it also anchors other proteins including ParC which recruits chemotaxis machinery and FlhG which involved in expression of flagella genes. Recent studies unveiled polar scaffolding proteins and their partners in many bacterial species.
Although these pole-organizing factors are diverse, bacteria appear to use overarching principles to arrange multiple macromolecular machineries to the specific site of the cell.
In this seminar, I will present our ongoing works to gain comprehensive view of organization at V. cholerae cell pole via HubP. First, we used comparative proteomics approach for further identification of polar proteins. We have identified 4 novel interaction partners of HubP: they include a penicillin binding protein and two proteins with unknown function. Lines of evidence indicated that the two new proteins are involved in cell motility. Second, we carry out super-resolution microscopy to define the precise spatial relationship among HubP, its interaction partners, and the cell pole. I will show our development of biological and informatics tools to integrate super-resolution microscopy data into multicellular analysis and succeeding investigation of precise localization.