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A novel RalGEF-like protein, RGL3, as a candidate effector for rit and Ras
1Department of Biochemistry, University of Kentucky College of Medicine, Lexington, Kentucky 40536-0230, USA.
The Journal of Biological Chemistry
|June 28, 2000
Summary
Researchers identified RGL3, a novel protein interacting with Rit and Ras small GTPases. RGL3 acts as a guanine nucleotide exchange factor for Ral, suggesting it
Area of Science:
- Molecular Biology
- Cell Signaling
- Oncogenesis
Background:
- The small GTPase Rit, a Ras relative, can induce oncogenic transformation.
- Rit's effector loop is similar to Ras, but it interacts with different effector proteins.
- Novel cellular targets are likely responsible for Rit's transforming activity.
Purpose of the Study:
- To identify Rit-binding proteins and understand Rit's cellular function.
- To investigate potential novel downstream effectors for Rit.
Main Methods:
- Yeast two-hybrid screening was employed to identify Rit-binding proteins.
- Interaction studies focused on the C-terminal Rit/Ras interaction domain of RGL3.
- Guanine nucleotide exchange activity of RGL3 toward Ral was assessed.
Main Results:
- RGL3 (Ral GEF-like 3) was identified as a Rit-binding protein.
- RGL3 shares sequence identity with known Ral guanine nucleotide exchange factors (RalGEFs).
- RGL3 interacts with Rit and Ras in a GTP- and effector loop-dependent manner.
- RGL3 exhibits guanine nucleotide exchange activity toward Ral, stimulated by activated Rit or Ras.
Conclusions:
- RGL3 functions as a guanine nucleotide exchange factor for the small GTPase Ral.
- RGL3 may act as a downstream effector for both Rit and Ras signaling pathways.
- These findings provide insight into the novel mechanisms of Rit-mediated oncogenesis.