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Updated: Jun 3, 2026
09:58
RhoC GTPase Activation Assay
Published on: August 22, 2010
The human Rgr oncogene is overexpressed in T-cell malignancies and induces transformation by acting as a GEF for Ras
K Osei-Sarfo1, L Martello, S Ibrahim
1Department of Pathology, New York University Langone Medical Center, New York, NY 10016, USA.
Oncogene
|March 29, 2011
Summary
The human hRgr oncogene, overexpressed in T-cell cancers, activates Ras and Ral GTPases, driving cell proliferation and invasion. Its catalytic activity is crucial for these oncogenic properties.
Area of Science:
- Molecular Biology
- Oncology
- Cellular Biology
Background:
- The Ras superfamily of GTPases regulates critical cellular functions like motility, proliferation, and differentiation.
- The RalGDS-related (Rgr) oncogene and its human orthologue, hRgr, were previously identified.
- A truncated form of hRgr (Dtr-hrgr) is overexpressed in T-cell neoplasms.
Purpose of the Study:
- To analyze hRgr transcript expression in human hematopoietic malignancies.
- To investigate the guanine nucleotide exchange factor (GEF) activity of hRgr.
- To determine the biological effects of hRgr and its catalytic-dead mutant on cell behavior.
Main Methods:
- Analysis of hRgr transcript levels in hematopoietic malignancies.
- Introduction of hRgr into fibroblast cell lines.
- In vitro guanine nucleotide exchange assays.
- Cell proliferation, invasion, anchorage dependence, and cell cycle assays.
Main Results:
- Dtr-hrgr was significantly overexpressed in many T-cell neoplasms.
- hRgr activated both Ral and Ras GTPases in vitro.
- hRgr enhanced cell proliferation, invasion, and S-phase progression while reducing anchorage dependence.
- These effects were abolished or reduced with the catalytic-dead mutant (cd) Dtr-hRgr.
Conclusions:
- hRgr functions as a guanine nucleotide exchange factor for Ral and Ras GTPases.
- The ability of hRgr to activate both Ral and Ras underlies its transformation-inducing phenotype.
- hRgr may be an important factor in the development of T-cell malignancies.
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