Systems-level interactions between insulin-EGF networks amplify mitogenic signaling

Area of Science:

• Cellular signaling
• Molecular biology
• Systems biology

Background:

• Signaling pathway crosstalk is less understood than individual pathways.
• Insulin and EGF signaling networks regulate cell growth and proliferation.
• Understanding crosstalk is vital for deciphering complex cellular responses.

Purpose of the Study:

• To investigate the crosstalk mechanisms between insulin and EGF signaling.
• To elucidate how this interplay potentiates mitogenic signaling.
• To identify key molecular nodes involved in signal amplification.

Main Methods:

• Combined experimental and computational modeling approaches.
• Utilized HEK293 cells to study Ras/ERK cascade activation.
• Investigated the roles of adaptor proteins (GAB1, IRS), Src kinase, and SHP2 phosphatase.

Main Results:

• Insulin poorly activates Ras/ERK but enhances EGF-induced ERK activation.
• Crosstalk mechanisms amplifying ERK signaling are upstream of Ras and at the Ras/Raf level.
• GAB1 and IRS mediate insulin's amplification of mitogenic signaling via PIP(3).
• GAB1 acts as a non-linear amplifier, and insulin confers robustness to GAB1 suppression.

Conclusions:

• Computational models can identify key targets for predicting cellular responses to combined stimuli.
• Insulin enhances EGF signaling robustness through GAB1 and IRS-mediated positive feedback.
• This study reveals critical crosstalk nodes potentiating mitogenic signaling.