Myosin II Controls Junction Fluctuations to Guide Epithelial Tissue Ordering.

Area of Science:

• Cell biology
• Biophysics
• Developmental biology

Background:

• Adherens junctions (AJs) are crucial for epithelial tissue integrity and morphogenesis.
• While AJ remodeling in development is well-studied, AJ dynamics under homeostasis remain less understood.
• Epithelia require fluidity to maintain tissue integrity against various forces.

Purpose of the Study:

• To investigate adherens junction (AJ) dynamics in epithelia experiencing increased packing order.
• To elucidate the role of junctional actomyosin in regulating neighbor exchange and tissue organization.
• To model the influence of local tension variance on topological transitions in epithelial tissues.

Main Methods:

• Studied AJ dynamics in an epithelial model with increasing packing order.
• Analyzed neighbor exchange events driven by junction length fluctuations.
• Investigated the regulation of these dynamics by junctional actomyosin and tension.

Main Results:

• Neighbor exchange events are driven by stochastic fluctuations in adherens junction length.
• Junctional actomyosin activity modulates the rate of neighbor exchange.
• Increased isotropic junctional actomyosin correlates with a reduced rate of neighbor exchange, enhancing tissue order.

Conclusions:

• Stochastic fluctuations in adherens junction length drive neighbor exchange events.
• Junctional actomyosin plays a regulatory role in controlling tissue topological transitions.
• Local tension variance dictates whether actomyosin forces inhibit or promote tissue refinement or deformation.