Multiple feedback mechanisms fine-tune Rho signaling to regulate morphogenetic outcomes

Area of Science:

• Cell biology
• Developmental biology
• Biophysics

Background:

• Rho signaling is crucial for generating cellular forces via actomyosin contractility.
• Understanding how Rho signaling dictates diverse cell morphologies remains a challenge.
• The Drosophila embryonic epithelium provides a model to study morphogenesis.

Purpose of the Study:

• Investigate how Rho signaling controls force asymmetry to drive epithelial morphogenesis.
• Elucidate the mechanisms underlying the 'alignment' process in Drosophila epithelia.
• Identify feedback mechanisms that regulate Rho signaling for precise morphological control.

Main Methods:

• Utilized Drosophila embryonic epithelium as a model system.
• Analyzed the role of Rho signaling pathway components (Rho, Rok, Dia) in cell shape changes.
• Investigated the impact of F-actin and Myosin-II (Myo-II) on Rho signaling and morphogenesis.

Main Results:

• Rho signaling, through Rok and Dia polarization, drives the formation of contractile actomyosin cables that align cells.
• Aberrant activation of Rho effectors leads to cell invagination instead of alignment.
• F-actin provides negative feedback on multiple points within the Rho signaling pathway.
• Rok mediates F-actin feedback to Rho independently of Myo-II.

Conclusions:

• Fine-tuning of Rho signaling is essential for generating specific cell geometries like aligned columns.
• Multiple feedback mechanisms, including F-actin-mediated negative feedback, regulate Rho signaling.
• These regulatory networks contribute to the diverse morphological outcomes observed in cellular development.