Actin-driven nanotopography promotes stable integrin adhesion formation in developing tissue.

Area of Science:

• Cell Biology
• Developmental Biology
• Biophysics

Background:

• Morphogenesis relies on stabilizing dynamic proteins into macromolecular structures.
• Integrin adhesions anchor muscles, resisting contractile forces, but their formation mechanisms are unclear.

Purpose of the Study:

• Investigate how integrin diffusion, immobilization, and activation occur during tissue development.
• Elucidate the role of actin-driven protrusions and membrane nanotopographies in forming muscle attachment sites (MASs).

Main Methods:

• Utilized super-resolution microscopy to visualize integrin and actin dynamics.
• Employed single-particle tracking to analyze protein diffusion and confinement.
• Experimented with isolated muscle cells and substrate nanotopography.

Main Results:

• Actin polymerization forms membrane protrusions with nanotopographies at MASs.
• Integrins assemble into adhesive belts around these protrusions, forming invadosome-like structures.
• Integrins and actin filaments become immobilized within nanotopographical diffusion traps during MAS development.
• Substrate nanotopography, not rigidity, drives adhesion maturation by controlling actin protrusion and integrin dynamics.

Conclusions:

• Actin-polymerization-driven membrane protrusions are crucial for establishing robust integrin adhesions in developing embryos.
• Membrane nanotopography plays a significant role in regulating integrin behavior and adhesion formation.
• Geometry is a key factor in the mechanical processes underlying morphogenesis.