ERRα coordinates actin and focal adhesion dynamics

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Cell migration is crucial for development and disease, relying on actin cytoskeleton and focal adhesion dynamics.
• The precise coordination of these processes is not fully understood.
• Oestrogen-related receptor α (ERRα) was previously identified as a key regulator of cell migration.

Purpose of the Study:

• To elucidate the mechanisms by which ERRα regulates cell migration.
• To investigate the role of ERRα in actin cytoskeleton organization and focal adhesion dynamics.
• To identify the specific pathways controlled by ERRα in these processes.

Main Methods:

• ERRα depletion using siRNA.
• Analysis of actin filament organization and cofilin activity.
• Assessment of cell adhesion and focal adhesion formation/turnover.
• Pharmacological inhibition of the RhoA-ROCK-LIMK-cofilin pathway.
• Investigation of MAP4K4 as a direct target of ERRα.

Main Results:

• Loss of ERRα resulted in abnormal actin accumulation and increased inactive cofilin.
• ERRα depletion led to decreased cell adhesion and impaired focal adhesion dynamics.
• Inhibition of the RhoA pathway rescued actin defects but not adhesion defects.
• MAP4K4 was identified as a direct target of ERRα, and its inhibition rescued adhesion and focal adhesion defects in ERRα-depleted cells.

Conclusions:

• ERRα is essential for coordinating actin dynamics and focal adhesion turnover during cell migration.
• ERRα regulates actin polymerization through the RhoA-ROCK-LIMK-cofilin pathway.
• ERRα controls cell adhesion and focal adhesion formation via direct regulation of MAP4K4.
• These findings reveal independent roles for ERRα in regulating distinct but coordinated cellular processes vital for migration.