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IGF1 Binding to Integrin αvβ3 Induces Direct Gα13 Binding to IGF1R Kinase
Yoko K Takada1, Chun-Yi Wu2, Yoshikazu Takada1,3
1Department of Dermatology, University of California School of Medicine, Research III Suite 3300, 4645 Second Ave., Sacramento, CA 95817, USA.
International Journal of Molecular Sciences
|May 13, 2026
Summary
Insulin-like growth factor 1 (IGF1) signaling activates cell survival through Gα13 binding to integrin β3 and the IGF1 receptor kinase. This interaction reveals a novel therapeutic target for IGF1-mediated pathways.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Insulin-like growth factor 1 (IGF1) is crucial for cell proliferation and survival.
- IGF1 binds to integrin αvβ3, forming a ternary complex with IGF1 receptor (IGF1R), but the activation mechanism is unclear.
- Guanine nucleotide-binding protein Gα13 interacts with integrin β3 and RhoA activation.
Purpose of the Study:
- To elucidate the mechanism of IGF1-induced IGF1R activation via integrin αvβ3.
- To investigate the role of Gα13 in IGF1 signaling.
- To identify potential therapeutic targets in the IGF1 signaling pathway.
Main Methods:
- Site-directed mutagenesis of integrin β3 tail (EEE/AAA) and Gα13 binding sites on IGF1R kinase and Gα13.
- Molecular docking simulations to predict binding interactions.
- Assessment of IGF1-induced cell survival and Gα13 binding to IGF1R kinase.
Main Results:
- Mutation of the integrin β3 tail EEE motif inhibited IGF1-induced cell survival, implicating Gα13.
- Docking simulations predicted a novel binding site for Gα13 on the IGF1R kinase.
- Mutations at predicted binding sites disrupted Gα13-IGF1R kinase interaction and inhibited IGF1-induced cell survival.
- A constitutively active Gα13 mutant (Q226L) inhibited cell survival, suggesting Gα13 binding to IGF1R kinase is critical.
Conclusions:
- IGF1 binding to αvβ3 promotes Gα13 recruitment to the β3 tail and subsequent binding to the IGF1R kinase, leading to IGF1R activation and cell survival.
- The Gα13 binding site on IGF1R kinase and the IGF1R binding site on Gα13 represent potential novel therapeutic targets.
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