Polychaetoid/ZO-1 strengthens cell junctions under tension while localizing differently than core adherens junction...

Area of Science:

• Cell biology
• Developmental biology
• Biophysics

Background:

• Embryonic development involves significant cell shape changes and movements.
• Robust linkage between cell-cell adherens junctions and the actomyosin cytoskeleton is essential for these processes.
• Mechanosensitive multiprotein complexes mediate this linkage through multivalent connections.

Purpose of the Study:

• To define the mechanism of action and functions of Drosophila polychaetoid (Pyd), a homolog of mammalian ZO-1.
• To investigate Pyd's role in reinforcing cell junctions and facilitating cell rearrangements during embryonic development.

Main Methods:

• Genetic analysis
• Cell biological techniques
• Computational modeling
• Structured illumination microscopy

Main Results:

• Pyd reinforces cell junctions under tension and is crucial for cell rearrangements.
• Absence of Pyd leads to stalled cell rearrangements and compromised junctional contractility.
• Pyd exhibits a distinct localization to strands extending from core junctional proteins, differing from cadherin-catenin and Cno.

Conclusions:

• Pyd plays a vital role in maintaining junctional integrity and enabling dynamic cell movements during embryogenesis.
• The molecular architecture of cell-cell junctions involves differential localization of proteins like Pyd, cadherin-catenin, and Cno.
• Distinct protein localizations and potential subcomplexes at the junction-cytoskeletal interface contribute to robust cell connections.