Related Experiment Video
Updated: May 18, 2026
09:58
RhoC GTPase Activation Assay
Published on: August 22, 2010
Coupling S100A4 to Rhotekin alters Rho signaling output in breast cancer cells
M Chen1, A R Bresnick, K L O'Connor
1Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
Oncogene
|September 12, 2012
Summary
Metastasis-associated protein S100A4 directly binds Rhotekin, linking S100A4 to Rho signaling. This interaction is crucial for RhoA function, promoting cell invasion and metastasis.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Rho signaling pathways are critical regulators of cell motility, invasion, and metastasis.
- Metastasis-associated protein S100A4 is implicated in cancer progression and invasion.
Purpose of the Study:
- To investigate the molecular mechanism by which S100A4 influences Rho signaling.
- To determine if S100A4 interacts with Rho effectors and modulates Rho pathway activity.
Main Methods:
- Glutathione S-transferase (GST) pull-down assays to assess direct binding.
- Immunoprecipitation assays to confirm protein complex formation.
- RNA interference (RNAi) to suppress gene expression.
- Three-dimensional (3D) cell culture to evaluate invasive growth.
Main Results:
- S100A4 directly binds to the Rho-binding domain (RBD) of Rhotekin in a calcium-dependent manner.
- S100A4, Rhotekin, and active RhoA form a ternary complex.
- Suppression of S100A4 and Rhotekin inhibits RhoA-dependent membrane ruffling and promotes stress fiber formation.
- Knockdown of S100A4 and Rhotekin blocks invasive growth in 3D cultures.
Conclusions:
- S100A4 interacts with Rhotekin to modulate RhoA signaling, switching its function from stress fiber formation to membrane ruffling.
- This S100A4-Rhotekin-RhoA interaction is essential for conferring an invasive cellular phenotype and promoting metastasis.
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