Cell adhesion suppresses autophagy via Src/FAK-mediated phosphorylation and inhibition of AMPK

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Autophagy is a crucial cellular process regulated by AMP-activated protein kinase (AMPK).
• AMPK activation, particularly through T172 phosphorylation, is vital for its signaling.
• Integrin-mediated cell adhesion activates the Src/Focal Adhesion Kinase (FAK) pathway, influencing cell survival.

Purpose of the Study:

• To investigate the interplay between Src signaling and AMPK-mediated autophagy.
• To identify novel regulatory mechanisms of autophagy in response to cell adhesion.
• To explore the therapeutic potential of targeting this pathway in cancer.

Main Methods:

• Utilized chemical inhibitors and genetic cell models.
• Employed targeted mutagenesis to study specific phosphorylation sites.
• Investigated autophagy induction under various stimuli, including glucose starvation.

Main Results:

• Src signaling phosphorylates the AMPK-α subunit at a novel site (tyrosine 179).
• This phosphorylation suppresses AMPK-T172 phosphorylation and inhibits autophagy during cell adhesion.
• Src and FAK were confirmed to suppress AMPK signaling and autophagy induced by glucose starvation.
• Combined treatment with hydroxychloroquine and Src inhibitors promoted apoptosis in cancer cells.

Conclusions:

• Src/FAK signaling directly inhibits AMPK and autophagy via novel tyrosine phosphorylation.
• This pathway is a key regulator of cellular homeostasis and is implicated in tumor progression.
• Targeting the Src/FAK-AMPK-autophagy axis presents a potential therapeutic strategy for cancer.