4-Hydroxynonenal activates Src through a non-canonical pathway that involves EGFR/PTP1B.

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Signaling

Background:

• Src is a critical non-receptor protein tyrosine kinase implicated in numerous biological processes.
• Src activation can occur via redox-dependent and independent pathways.
• 4-Hydroxy-2-nonenal (HNE), a product of lipid peroxidation, is elevated in conditions linked to Src activation.

Purpose of the Study:

• To elucidate the mechanism by which HNE activates human c-Src.
• To investigate the role of canonical and non-canonical pathways in HNE-mediated Src activation.

Main Methods:

• Dose- and time-dependent assays to measure Src activation and phosphorylation.
• Utilized a Protein Tyrosine Phosphatase 1B (PTP1B) inhibitor (539741).
• Employed an Epidermal Growth Factor Receptor (EGFR) inhibitor (AG1478) and EGFR gene silencing.

Main Results:

• HNE dose- and time-dependently increased Src activation and phosphorylation at Tyr530 (pTyr530 Src), indicating non-canonical activation.
• PTP1B inhibition enhanced basal Src activity but reduced HNE-mediated Src activation.
• EGFR inhibition or silencing abrogated HNE-induced EGFR activation and suppressed both basal and HNE-induced Src activity.
• AG1478 also reversed the Src activation induced by PTP1B inhibition.

Conclusions:

• HNE activates Src through a non-canonical pathway.
• This pathway involves the activation of EGFR and the inhibition of PTP1B.
• These findings provide novel insights into the molecular mechanisms of Src activation by oxidative stress products.