Envelope stress responses: balancing damage repair and toxicity

Area of Science:

• Microbiology
• Cell Biology
• Bacterial Physiology

Background:

• The Gram-negative bacterial envelope is crucial for cell survival, comprising the inner membrane, periplasm, peptidoglycan, and outer membrane.
• Environmental fluctuations and intrinsic factors can damage this envelope, necessitating robust cellular defense mechanisms.
• Envelope stress responses are vital for maintaining bacterial homeostasis under adverse conditions.

Purpose of the Study:

• To comprehensively review the causes of Gram-negative envelope stress.
• To elucidate the cellular pathways involved in responding to and mitigating envelope stress.
• To discuss the consequences of aberrant or excessive stress response activation.

Main Methods:

• This is a review article, synthesizing existing research on bacterial envelope stress.
• It analyzes the mechanisms of various envelope stress response pathways.
• Focuses on the role of the sigma E (σE) response in preventing cell death.

Main Results:

• Envelope stress can arise from diverse environmental and intrinsic triggers.
• Specific response pathways, including the σE pathway, are activated to counteract stress.
• Dysregulated stress responses, either insufficient or excessive, lead to cellular damage and can be detrimental.

Conclusions:

• Proper regulation of envelope stress responses is essential for bacterial survival.
• Aberrant activation of these pathways, even in the absence of stress, can cause significant cellular harm.
• The σE response plays a critical role in preventing cell death from toxic unfolded proteins.