# mSphere of Influence: Celebrating exceptions to the rule of lipid A essentiality

## TL;DR

This article discusses how certain bacteria can survive without essential cell envelope components, challenging current understanding of bacterial survival mechanisms.

## Contribution

The paper highlights novel bacterial exceptions to lipid A essentiality, offering new perspectives on cell envelope biology.

## Key findings

- Some bacteria can survive without typical lipid A structures.
- Anionic sphingolipids may compensate for missing lipid A in certain conditions.
- These findings reveal gaps in understanding bacterial envelope regulation.

## Abstract

Kate Hummels works in the field of bacterial cell envelope biosynthesis and studies the regulation of the metabolic pathways needed to build the Gram-negative cell envelope. In this mSphere of Influence article, she reflects on how the papers “A penicillin-binding protein inhibits selection of colistin-resistant, lipopoligosaccharide-deficient Acinetobacter baumannii” by Boll et al. and “Caulobacter lipid A is conditionally dispensable in the absence of fur and in the presence of anionic sphingolipids” by Zik et al. made an impact on her by studying organisms that deviate from accepted norms to highlight the plethora of unanswered questions in cell envelope biology.