RhoA and RhoC have distinct roles in migration and invasion by acting through different targets

Area of Science:

• Cell biology
• Molecular biology
• Biochemistry

Background:

• RhoA and RhoC are highly similar small GTPases with poorly understood differential roles in cell migration and invasion.
• Understanding the molecular mechanisms underlying these differences is crucial for cancer research and therapeutic development.

Purpose of the Study:

• To elucidate the distinct molecular mechanisms by which RhoA and RhoC regulate cell migration and invasion.
• To identify novel targets and pathways involved in RhoA and RhoC signaling.

Main Methods:

• RNA interference (RNAi) to deplete RhoA and RhoC.
• Analysis of cell morphology, protrusion dynamics, and migratory behavior in 2D and 3D.
• Investigated the roles of Rho-associated protein kinases (ROCK1/2) and formin FMNL3.

Main Results:

• RhoA depletion resulted in elongated cells with multiple Rac1-driven protrusions, increasing invasion, mediated by ROCK1 and ROCK2.
• ROCK2 depletion impaired polarity, while ROCK1 depletion affected cell elongation and retraction.
• RhoC depletion increased cell spreading, inhibited directed migration and invasion, and involved Rac1 activation and the novel RhoC target FMNL3.

Conclusions:

• RhoA promotes cell polarity through ROCK2-mediated Rac1 suppression in lamellipodia.
• RhoC facilitates polarized migration by using FMNL3 to limit lamellipodial broadening.
• These findings reveal distinct molecular strategies employed by RhoA and RhoC in regulating cell migration and invasion.