Cellular Blebs and Membrane Invaginations Are Coupled through Membrane Tension Buffering

Area of Science:

• Cell Biology
• Biophysics

Background:

• Bleb-type cellular protrusions are crucial for biological processes.
• Bleb growth is supported by membrane from tubular invaginations, but their interaction is unclear.
• Tubular invaginations may act as a membrane reservoir or increase cell tension, suppressing protrusions.

Purpose of the Study:

• Investigate the dual role of membrane tubes in bleb expansion.
• Understand the interplay between blebs and tubular invaginations.
• Clarify how membrane tubulation proteins affect cell membrane tension and deformation.

Main Methods:

• Physical modeling of cell membrane dynamics.
• In vivo experimental validation.
• Analysis of protein concentration effects on blebbing.

Main Results:

• The model replicates the tube-flattening mode of bleb expansion.
• Increased concentration of curved membrane proteins reduces blebbing rate.
• Cortical myosin contractility counterbalances the stabilizing effect of membrane tubes.

Conclusions:

• Proteins inducing membrane tubulation, like N-BAR domain proteins, can buffer effective membrane tension.
• Membrane tension is a key regulator of cell deformations.
• The study elucidates the complex relationship between membrane structures and cell dynamics.