Mechanical tension drives cell membrane fusion

Area of Science:

• Cell biology
• Biophysics
• Mechanobiology

Background:

• Membrane fusion is essential for cellular processes but requires overcoming significant energy barriers for lipid bilayer apposition.
• Cell-cell fusion is an asymmetric process, with an attacking cell forming protrusions into a receiving cell.
• The precise mechanisms by which cells manage the energy demands of membrane fusion remain incompletely understood.

Purpose of the Study:

• To elucidate the role of the receiving cell's response in overcoming membrane fusion energy barriers.
• To investigate the function of Myosin II (MyoII) as a mechanosensor during cell-cell fusion.
• To understand how mechanical forces and chemical signaling cooperate to facilitate fusion.

Main Methods:

• Investigated the mechanosensory response of the receiving cell during cell-cell fusion.
• Examined the role of Myosin II (MyoII) recruitment and function at the fusion site.
• Analyzed the interplay between MyoII-mediated force generation and signaling from cell adhesion molecules.

Main Results:

• The receiving cell employs a Myosin II (MyoII)-mediated mechanosensory response to its fusion partner.
• MyoII is force-inducibly recruited to the fusion site, with its response amplified by cell adhesion molecule signaling.
• Accumulated MyoII enhances cortical tension, promoting fusion pore formation and driving membrane fusion.

Conclusions:

• Cell-cell fusion is facilitated by a Myosin II (MyoII)-driven mechanosensory response in the receiving cell.
• Mechanical tension generated at the fusogenic synapse, mediated by protrusive and resisting forces, is crucial for overcoming fusion energy barriers.
• This integrated mechanical and chemical signaling pathway drives efficient cell membrane fusion.