Actomyosin fibers DApPLE epithelial apical junctions

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Epithelial cell morphology is crucial for maintaining tissue function and overall homeostasis.
• The precise molecular mechanisms governing cell shape establishment, particularly the connection between polarity and the cytoskeleton, are not fully understood.

Purpose of the Study:

• To identify key molecular players linking cellular polarity complexes to the actomyosin cytoskeleton at apical junctions.
• To elucidate the signaling pathways regulated by these linkers in establishing and maintaining epithelial cell shape.

Main Methods:

• Immunofluorescence microscopy to visualize protein localization at apical junctions.
• Biochemical assays to study protein-protein interactions and signaling pathway activation.
• Genetic manipulation (e.g., knockdowns or mutations) to assess the functional role of identified proteins.

Main Results:

• DAPLE (Dishevelled-associated protein in the lateral epicardium) was identified as a critical linker protein at apical junctions.
• DAPLE was shown to recruit the protein CD2P (Cytoplasmic dynein light chain-associated protein).
• DAPLE activation of Gαβγ-mediated RhoA signaling was demonstrated, which is essential for regulating actomyosin contractility.

Conclusions:

• DAPLE acts as a crucial molecular bridge connecting apical polarity complexes with the actomyosin cytoskeleton.
• The DAPLE-CD2P-Gαβγ-RhoA signaling axis is vital for establishing and maintaining proper epithelial cell morphology and function.
• These findings provide new insights into the regulation of cell shape, a fundamental aspect of cellular homeostasis.