In Vivo Retention of Protein Aggregates in Escherichia Coli

Recently, it has been established that Escherichia coli cells accumulate protein aggregates at their polar regions. Using fluorescent tagging of IbpA proteins, which are known to co - localize with protein aggregates, it has b een further shown by following the aggregates along cell lineages that, due to their retention at the poles, they become asymmetrically distributed by the cells of the lineage. However, there is no evidence for a transport mechanism responsible for the acc umulation at the poles. Instead, it has been hypothesized that this process is associated with the presence of the nucleoid at midcell. Here, we describe ongoing as well as planned measurements which aim to establish and characterize the role of the nucleo id in the processes of segregation and subsequent retention of protein complexes at the cellular poles. In particular, in these experiments, we will change the size of the nucleoid by subjecting cells to different media and chemical stress conditions and observe the consequences on the spatial distribution of the complexes. For this, we are using E. coli MGAY strain expressing the fluorescent IbpA - YFP proteins and DAPI (4', 6- diamidino -2- phenylindole) staining of the nucleoid. Finally, we will present preli minary results that suggest that the segregation and retention of aggregates at the cell poles, while it a robust process, it is not immune to perturbations of the nucleoid structure, which provides supporting evidence that the nucleoid plays a role in the segregation and subsequent retention of these unwanted protein aggregates