Mechanosensitive Junction Remodeling Promotes Robust Epithelial Morphogenesis

Area of Science:

• Cell Biology
• Biophysics
• Developmental Biology

Background:

• Epithelial morphogenesis relies on coordinated cell shape changes.
• Pulsatile contractions of intercellular junctions drive tissue-scale deformations in vivo.
• The mechanism and function of this pulsatile ratcheting remain unclear.

Purpose of the Study:

• To investigate the mechanistic basis of irreversible deformations in epithelial tissue.
• To understand how pulsatile contractions lead to robust epithelial shape changes.
• To develop a model that captures the observed junctional mechanics during morphogenesis.

Main Methods:

• Combined theoretical modeling with biophysical experiments.
• Utilized optogenetic control of actomyosin contractility.
• Developed a modified vertex model incorporating thresholded tension remodeling and continuous strain relaxation.

Main Results:

• Epithelial junctions exhibit elastic behavior under low stress but irreversible deformation under high stress.
• Existing models failed to replicate these mechanosensitive junction behaviors.
• The proposed model, with thresholded remodeling and strain relaxation, accurately describes experimental findings.

Conclusions:

• Mechanosensitive tension remodeling and continuous strain relaxation are key to epithelial junction mechanics.
• This combination provides a robust mechanism for large-scale tissue morphogenesis.
• The pulsatile ratcheting of junctions drives irreversible deformations essential for development.