Related Experiment Videos
SETA is a multifunctional adapter protein with three SH3 domains that binds Grb2, Cbl, and the novel SB1 proteins
S C Borinstein1, M A Hyatt, V W Sykes
1Department of Anatomy, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA.
Abstract:
Expression of the src homology 3 (SH3)-encoding, expressed in tumorigenic astrocytes (SETA) gene is associated with astrocyte transformation in culture and tumors in the adult brain. SETA binds to the apoptosis regulator apoptosis-linked gene 2 (ALG-2) interacting protein 1 (AIP1), and modulates apoptosis in astrocytes. The predicted protein structure of SETA revealed two SH3 domains, while related proteins were reported to have three. Here we report the identification of an additional SH3 domain N-terminal to the previously identified SETA sequence. Yeast two-hybrid screening of a p53(-/-) astrocyte cDNA library with this SH3 domain identified a novel gene, SETA binding protein 1 (SB1), with 55% amino acid identity to the renal tumor antigen, NY-REN-45. In vitro confrontation and co-immunoprecipitation experiments confirmed the binding of SB1 to SETA. Evidence that SETA binds to the CD2 protein, the proto-oncogene c-Cbl, and the signal transduction molecule Grb2, and can dimerize via its C-terminal coiled coil (CC) domain is also presented.
Insights
The SETA gene, linked to astrocyte tumors, has an additional SH3 domain. This domain helps identify a new binding protein, SB1, which interacts with SETA and influences astrocyte apoptosis.
Area of Science:
- Molecular Biology
- Cancer Research
- Neuroscience
Background:
- The src homology 3 (SH3)-encoding, expressed in tumorigenic astrocytes (SETA) gene is implicated in astrocyte transformation and brain tumors.
- SETA interacts with apoptosis regulator AIP1, modulating astrocyte apoptosis.
- Previous structural analysis indicated two SH3 domains in SETA, contrary to related proteins with three.
Purpose of the Study:
- To identify novel proteins interacting with SETA.
- To characterize the function of SETA and its binding partners in astrocyte biology.
- To investigate the role of SETA in tumorigenesis.
Main Methods:
- Yeast two-hybrid screening of a p53(-/-) astrocyte cDNA library.
- In vitro confrontation assays.
- Co-immunoprecipitation experiments.
Main Results:
- An additional N-terminal SH3 domain was identified in SETA.
- A novel gene, SETA binding protein 1 (SB1), was identified through yeast two-hybrid screening.
- SB1 demonstrated 55% amino acid identity to the renal tumor antigen NY-REN-45.
- Binding of SB1 to SETA was confirmed via in vitro and co-immunoprecipitation experiments.
- SETA was shown to bind CD2, c-Cbl, and Grb2, and to dimerize via its C-terminal coiled coil domain.
Conclusions:
- The discovery of an additional SH3 domain in SETA expands our understanding of its structure.
- SB1 is a novel SETA-binding protein with potential roles in astrocyte biology and tumorigenesis.
- SETA's interactions with multiple proteins suggest a role in complex signaling pathways relevant to cancer.