DAPLE orchestrates apical actomyosin assembly from junctional polarity complexes.

Area of Science:

• Cell Biology
• Epithelial Biology
• Cytoskeletal Dynamics

Background:

• Epithelial cells require coordinated polarity and cytoskeletal organization for proper function.
• The molecular mechanisms linking polarity complexes to cytoskeletal regulation of cell shape are not fully understood.

Purpose of the Study:

• To elucidate the mechanism by which the PAR polarity complex influences cytoskeletal organization at apical junctions.
• To identify the molecular players involved in translating polarity cues into cytoskeletal dynamics.

Main Methods:

• Investigated the role of the PAR polarity complex (PAR3-PAR6-aPKC) in epithelial cell morphology.
• Utilized techniques to identify proteins recruited by the PAR complex to apical junctions.
• Examined the downstream effects of recruited proteins on actin stabilization and RhoA-myosin signaling.

Main Results:

• The PAR polarity complex recruits DAPLE to apical cell junctions.
• DAPLE triggers a two-pronged mechanism for apical actomyosin assembly.
• DAPLE recruits CD2AP for actin stabilization and activates G protein signaling for RhoA-myosin activation.

Conclusions:

• DAPLE acts as a direct molecular link between junctional polarity complexes and apical cytoskeletal assemblies.
• This pathway is crucial for maintaining epithelial cell morphology.
• The findings reveal a novel mechanism for regulating cell shape through polarity-cytoskeleton crosstalk.