Persistent cell contacts enable E-cadherin/HMR-1- and PAR-3-based symmetry breaking within a developing C. elegans...

Organizing cell polarity across tissues remains a central question in developmental biology. While individual cell polarization is well studied, how cells coordinate polarity with neighbors remains unclear. Previous work has shown that epithelial cells use PAR proteins to establish polarity domains. However, how these domains align tissue-wide was not fully understood. This paper addresses a gap in understanding how persistent cell contacts influence polarity coordination. Earlier studies suggested that cell-cell adhesion proteins like E-cadherin could play signaling roles beyond adhesion. The current work builds on this by exploring how contact duration affects polarity formation. No prior work had resolved how transient versus stable contacts shape tissue polarity. This study introduces a new framework where contact lifetime informs polarity patterning. By focusing on C. elegans intestinal cells, the authors examine a system with minimal molecular asymmetry. Their findings may apply broadly to epithelial development in other species.

The study aimed to uncover how epithelial cells coordinate polarity without obvious molecular asymmetries. The researchers focused on the C. elegans intestinal epithelium, a system with minimal known polarity cues. They sought to determine if contact duration could serve as a patterning cue. The goal was to identify the molecular players involved in this process. The team hypothesized that cell contact lifetime might influence polarity formation. They tested whether PAR-3 and HMR-1 could mediate this coordination. The study also aimed to clarify how local polarity complexes form and migrate. Understanding these mechanisms could explain tissue-wide symmetry breaking in epithelia.

The researchers used C. elegans intestinal cells as a model system. They employed live imaging to track polarity complex dynamics. Fluorescent markers were used to visualize PAR-3 and HMR-1 localization. Time-lapse microscopy captured contact lifetime asymmetries. The team analyzed how LPCs form at homotypic contacts. They observed how these complexes migrate toward a midline. Computational modeling helped interpret contact lifetime patterns. The study combined genetic manipulation with quantitative imaging to test hypotheses.

The study found that LPCs form at homotypic contacts with longer lifetimes. These complexes recruit apical determinants into punctate structures. PAR-3 and HMR-1 colocalize in these complexes. The complexes then migrate toward a shared midline. This migration establishes tissue-wide polarity. Contact duration differences drive where LPCs persist. Oriented cell divisions and neighbor exchanges create these differences. The findings suggest a conserved mechanism for epithelial symmetry breaking.

The authors propose that contact lifetime asymmetry drives polarity coordination. They suggest that PAR-3 and HMR-1 mediate this process. The study shows that LPCs form at stable homotypic contacts. These complexes then migrate to establish tissue-wide polarity. The findings suggest a non-adhesive role for HMR-1 in signaling. The researchers argue that this mechanism may be conserved across epithelia. They suggest that neighbor exchanges and oriented divisions create patterning cues. Their work provides a framework for understanding epithelial symmetry breaking.