14-3-3 proteins regulate desmosomal adhesion via plakophilins

Area of Science:

• Cell biology
• Molecular biology
• Biochemistry

Background:

• Desmosomes are crucial for epithelial tissue integrity and mechanical stress resistance.
• Desmosome dynamics are essential for tissue remodeling but poorly understood.
• Protein phosphorylation is implicated in regulating desmosome assembly and stability.

Purpose of the Study:

• To investigate the role of growth factor signaling in desmosome regulation.
• To identify proteins interacting with plakophilins (PKP1, PKP3) in a phosphorylation-dependent manner.
• To elucidate the specific functions of 14-3-3 protein isoforms in controlling desmosome dynamics.

Main Methods:

• Co-immunoprecipitation assays to study protein interactions.
• Analysis of protein phosphorylation sites (e.g., S155, S285).
• Immunofluorescence microscopy to assess desmosome localization and keratinocyte cohesion.

Main Results:

• Growth factor signaling modulates PKP1 and PKP3 association with 14-3-3 proteins.
• 14-3-3γ binds phosphorylated PKP1, reducing keratinocyte intercellular cohesion.
• 14-3-3σ binds phosphorylated PKP3, enhancing desmosome stability at tricellular contacts.

Conclusions:

• 14-3-3 proteins represent a novel regulatory mechanism for desmosome function.
• Specific 14-3-3 isoforms exert distinct, sometimes opposing, effects on intercellular adhesion.
• Phosphorylation-dependent interactions with 14-3-3 proteins control desmosome dynamics and tissue stability.