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Membrane homeostasis beyond fluidity: control of membrane compressibility
1Medical Biochemistry and Molecular Biology, Medical Faculty, Saarland University, Homburg, Germany; PZMS, Center for Molecular Signaling, Medical Faculty, Saarland University, Homburg, Germany.
Trends in Biochemical Sciences
|August 31, 2023
Summary
Homeoviscous adaptation is key for cell function. This study reveals membrane thickness and compressibility are vital for protein function, proposing the unfolded protein response (UPR) maintains endoplasmic reticulum (ER) membrane homeostasis.
Area of Science:
- Cell biology
- Biochemistry
- Membrane biophysics
Background:
- Biomembranes, composed of lipids and proteins, compartmentalize cellular biochemistry.
- Membranes dynamically remodel in response to physical, metabolic, and stress cues.
- Homeoviscous adaptation is a known example of membrane responsiveness.
Purpose of the Study:
- To discuss limitations and misconceptions of homeoviscous adaptation.
- To highlight the importance of membrane thickness and compressibility for transmembrane protein lifecycle.
- To propose the unfolded protein response (UPR) as a mechanism for endoplasmic reticulum (ER) membrane homeostasis.
Main Methods:
- Review of existing literature on membrane biophysics and protein dynamics.
- Analysis of key stages in transmembrane protein life cycle.
- Hypothesizing the role of UPR in sensing and correcting membrane mechanical properties.
Main Results:
- Identified critical roles for membrane thickness and compressibility in protein insertion, function, sorting, and inheritance.
- Proposed that aberrant transverse membrane stiffening is sensed by the UPR.
- Suggested UPR triggers adaptive responses to restore membrane compressibility.
Conclusions:
- Membrane thickness and compressibility are essential for proper transmembrane protein function.
- The unfolded protein response (UPR) is implicated in maintaining endoplasmic reticulum (ER) membrane homeostasis.
- UPR acts as a sensor for membrane mechanical defects, initiating corrective adaptations.
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