A key step of bacterial cytochinesis is the dynamic assembly of the division proteins into a machinery called divisome. We described the division interactome of Escherichia coli and Streptococcus pneumoniae. Our results showed that the protein-protein interaction (PPI) web is extremely complex: generally, each protein undergoes multiple interactions with both itself and other partners to form multimeric complexes. One of the main problems in the PPI studies is to determine the biological role of each interaction and the behaviour of interaction-defective mutants can furnish an answer to this question. To establish whether an interaction has a biological role, the mutated gene is inserted in a bacterial strain where the same gene, deleted in the chromosome, is cloned in a plasmid under the control of an inducible promoter. If the interaction is essential for the bacterial viability, the mutated gene will not be able to sustain the bacterial growth. The ability of the mutated gene to recruit to the septum the proteins with which it loses the interaction ability was also analyzed. We selected and studied mutants impaired in the interaction ability with each of the FtsQ partner. Since in the case of FtsQ two protein domains are independently involved in interaction with some partner proteins, as FtsN, mutation in one domain is suppressed by the presence of the second interaction domain still functional. Therefore, to analyze the biological role of FtsQ-FtsN interaction, double mutants, localized in both domains, were constructed by in vitro recombination and their behaviour is described in this poster. In addition, FtsQ forms a trimeric complex with FtsL and FtsB, necessary for linking the upstream mainly cytoplasmic division proteins with the downstream periplasmic proteins. Since FtsQ mutants characterised by the loss of interaction with either FtsB or FtsL did not show reduced FtsQ functionality, we hypothesised that, if the FtsQ interaction with one member of the complex was impaired by a mutation, the interaction of FtsQ with the other protein, and/or the interaction of the two proteins with each other, would allow complex formation. To test this hypothesis, we constructed, and describe in this poster, the behaviour of a FtsQ double mutant impaired in its interaction with both proteins.
Essential and not essential interactions in interactome networks: the case of E. coli division protein FtsQ interactions
Ghelardini P
2012
Abstract
A key step of bacterial cytochinesis is the dynamic assembly of the division proteins into a machinery called divisome. We described the division interactome of Escherichia coli and Streptococcus pneumoniae. Our results showed that the protein-protein interaction (PPI) web is extremely complex: generally, each protein undergoes multiple interactions with both itself and other partners to form multimeric complexes. One of the main problems in the PPI studies is to determine the biological role of each interaction and the behaviour of interaction-defective mutants can furnish an answer to this question. To establish whether an interaction has a biological role, the mutated gene is inserted in a bacterial strain where the same gene, deleted in the chromosome, is cloned in a plasmid under the control of an inducible promoter. If the interaction is essential for the bacterial viability, the mutated gene will not be able to sustain the bacterial growth. The ability of the mutated gene to recruit to the septum the proteins with which it loses the interaction ability was also analyzed. We selected and studied mutants impaired in the interaction ability with each of the FtsQ partner. Since in the case of FtsQ two protein domains are independently involved in interaction with some partner proteins, as FtsN, mutation in one domain is suppressed by the presence of the second interaction domain still functional. Therefore, to analyze the biological role of FtsQ-FtsN interaction, double mutants, localized in both domains, were constructed by in vitro recombination and their behaviour is described in this poster. In addition, FtsQ forms a trimeric complex with FtsL and FtsB, necessary for linking the upstream mainly cytoplasmic division proteins with the downstream periplasmic proteins. Since FtsQ mutants characterised by the loss of interaction with either FtsB or FtsL did not show reduced FtsQ functionality, we hypothesised that, if the FtsQ interaction with one member of the complex was impaired by a mutation, the interaction of FtsQ with the other protein, and/or the interaction of the two proteins with each other, would allow complex formation. To test this hypothesis, we constructed, and describe in this poster, the behaviour of a FtsQ double mutant impaired in its interaction with both proteins.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
