LsrK Kinase Inhibitors

E. coli LsrK Kinase Inhibitors as Quorum Sensing interfering agents: validation of therapeutic potential (WP1-3)

Dr. Fabrizio Giordanetto
Taros Chemicals

Many enteric bacteria communicate with one another using “quorum sensing” (QS), which enables the bacterial ensemble to coordinate gene expression with the population cell density. One important QS signal is AI-2, which has been proposed to impact on the regulation of a variety of important genes (including those involved in virulence, type III secretion, motility and cell division). The AI-2 molecule (4,5-dihydroxy-2,3-pentanedione or DPD) is made by an enzyme called LuxS, present in many different species of bacteria. In gut enterics such as S. typhimurium and E. coli, DPD stimulates expression of an operon encoding a transport apparatus known as the LuxS-Regulated transporter (Lsr). The function of the Lsr transporter is to internalize and trap AI-2. LsrK is a key part of the lsr operon; this protein is a kinase, which phosphorylates AI-2 (Xavier & Bassler, 2005. J. Bacteriol. 187, 238–248). In the phospho-form, AI-2 binds to a transcriptional regulator called LsrR, thereby de-repressing the lsr operon (and possibly also affecting the expression of other, non-lsr genes too). This way, lsr operon expression increases and a positive feedback loop is established. Consequently, lsrK mutants are null for AI-2 dependent QS and the LsrK enzyme is increasingly being recognized as an excellent target for the development of novel anti-infective strategies. The aim of our project is to use a combination of structure-based design, biochemical screening, medicinal chemistry and chemical biology, to develop and validate the first LsrK kinase inhibitors and associated chemical probes. These will be further characterized at a functional cellular and biochemical level to assess their detailed mechanism of action and impact on E. coli survival. 

Objectives: Identify the first E. coli LsrK kinase inhibitors and evaluate their ability to impair bacterial growth based on QS interference. Assessment of whether QS inhibition is a feasible approach for antibacterial purposes.

Expected Results: Validation of the functional consequences of LsrK inhibition on QS in E. coli, assessment of LsrK inhibitors for drug discovery applications and their therapeutic potential.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska Curie grant agreement No  642620
European Union