RhoA regulates actin network dynamics during apical surface emergence in multiciliated epithelial cells

Area of Science:

• Cell Biology
• Epithelial Biology
• Developmental Biology

Background:

• Epithelial cell replacement involves progenitor cell specification, radial intercalation, and apical surface emergence.
• Actin-based pushing, controlled by formin 1 (Fmn1), drives apical emergence in nascent multiciliated epithelial cells (MCCs).
• The precise regulation of Fmn1 and the associated actin network remains largely unknown.

Purpose of the Study:

• To investigate the role of the small GTPase RhoA in the apical emergence of MCCs.
• To elucidate the molecular mechanisms controlling Fmn1 activity and apical actin network assembly.
• To understand RhoA's contribution to the forces governing apical surface expansion.

Main Methods:

• Disruption of RhoA function in MCCs.
• Quantitative time-lapse imaging.
• Fluorescence recovery after photobleaching (FRAP) studies.
• Cell shape analysis.

Main Results:

• Disrupting RhoA function decreased the rate and final size of apical surface expansion.
• RhoA influences the balance of forces acting on the MCC apical surface.
• RhoA functions with Fmn1 to control the assembly of the apical actin network in MCCs.

Conclusions:

• RhoA is a key regulator of apical surface assembly in MCCs, working in conjunction with Fmn1.
• These findings offer new molecular insights into epithelial apical surface formation.
• The study may shed light on mechanisms underlying apical lumen formation in epithelial tissues.