Mechanical forces used for cell fractionation can create hybrid membrane vesicles

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• Understanding intracellular processes necessitates separating membrane-enclosed compartments.
• Mechanical disruption of the plasma membrane (PM) is a common cell investigation technique.
• The potential for vesicle fusion between different membrane sources post-disruption remains unclear.

Purpose of the Study:

• To investigate whether mechanical cell disruption causes fusion between different membrane types.
• To quantify the extent of potential membrane fusion during cellular fractionation.
• To assess the validity of conclusions drawn from techniques involving cell disruption.

Main Methods:

• Utilized specific markers for the endoplasmic reticulum (ER) and plasma membrane (PM).
• Employed flow cytometry and immuno-electron microscopy (immuno EM) to detect membrane origins.
• Analyzed membrane entities generated during mechanical cell disruption.

Main Results:

• Fractionation processes generated a small fraction of new membrane entities from distinct origins (PM and ER).
• This fusion occurred in a temperature-independent manner during initial disruption.
• The number of fused vesicles was found to be minimal.

Conclusions:

• Mechanical cell disruption can lead to the formation of mixed membrane vesicles.
• The observed fusion events are minimal and do not invalidate studies using these methods.
• Conclusions regarding organelles or fusion events are valid if they exceed the low level of artifactual fusion.