Shaping the bacterial envelope: Interplay between the components and impact on antibiotic resistance

Introduction

Gram-negative bacteria are notoriously resilient, dominating the list of pathogens requiring urgent medical attention. Fundamental to their remarkable antibiotic resistance is a tripartite envelope comprised of an inner membrane (IM), peptidoglycan cell wall (PG), and an outer membrane (OM). While these layers were previously viewed as separate compartments, it is becoming apparent that they work together in order to maintain envelope integrity.

Research Gap

However, little is known about the crosstalk between components and the molecular mechanisms orchestrating envelope assembly and functionality. Our latest work has identified a key interaction between the PG and the BAM complex, which inserts new OM proteins (OMPs), revealing a mechanism coordinating PG and OMP biogenesis and directing them both to the cell center.

Hypothesis

We posit that coordination is a key principle of envelope assembly and that multiple interactions among envelope constituents are waiting to be discovered.

Project Goals

In Shape-En-Resist, we will uncover novel physical and genetic interactions, identify coordination mechanisms, and elucidate their impact on bacterial physiology and antibiotic resistance. To this end, we will focus on three aims:

1. Explore the assembly of lipopolysaccharide (LPS), an endotoxin covering the bacterial surface, and characterize its interplay with envelope biogenesis.
2. Comprehensively map PG-OMP interactions and study how they affect bacterial response to antibiotics.
3. Uncover the outcomes of spatially heterogeneous envelope biogenesis and whether this process is a source of phenotypic diversity.

Methodology

To address these questions, a multidisciplinary approach will be taken, combining cutting-edge microscopy, advanced genetic screens, proteomics, and novel functionality assays.

Expected Outcomes

We expect this project to uncover the interaction network amongst envelope components, reveal how it impacts the physiology of both single cells and bacterial populations, and ultimately expose the secrets of bacterial resilience.