Cell repair: Revisiting the patch hypothesis.

Area of Science:

• Cell Biology
• Membrane Biology
• Wound Healing

Background:

• Plasma membrane damage triggers cellular repair mechanisms.
• Membrane resealing is hypothesized to involve fusion of intracellular compartments to form a patch.
• Visual confirmation of this patch hypothesis has been challenging.

Purpose of the Study:

• To directly visualize the membrane fusion events during plasma membrane repair.
• To confirm the efficacy of the hypothesized patch in resealing membrane damage.
• To investigate associated changes in the plasma membrane and subcellular organization.

Main Methods:

• Utilized advanced microscopy with high spatiotemporal resolution.
• Studied wounded *Xenopus laevis* oocytes.
• Observed membrane fusion and lipid remodeling dynamics.

Main Results:

• Provided the first direct visualization of membrane fusion events forming a resealing patch.
• Demonstrated the patch's ability to rapidly abate material exchange across the plasma membrane within seconds.
• Observed significant lipid remodeling and both conventional (exocytosis) and novel (explodosis) membrane fusion events.
• Revealed complex wound-induced subcellular patterning and signaling pathway interactions.

Conclusions:

• The patch hypothesis for membrane resealing is visually confirmed.
• Membrane repair involves rapid fusion events and significant plasma membrane remodeling.
• Cellular wound response is shaped by intricate interactions between lipid, protein, and ionic signaling.