Optogenetic control of focal adhesion kinase signaling

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Focal adhesion kinase (FAK) is a key regulator of cellular processes including adhesion, motility, survival, and proliferation.
• FAK integrates signals from integrins, growth factor receptors, and mechanical stress.
• Understanding FAK's precise role requires tools for controlled activation and investigation.

Purpose of the Study:

• To develop a novel photo-activatable focal adhesion kinase (FAK) system.
• To investigate the rapid and reversible activation of FAK using blue light.
• To explore FAK's downstream signaling pathways and biological functions.

Main Methods:

• Development of a single-component, photo-activatable FAK (optoFAK) using cryptochrome 2 (CRY2) and blue light-induced oligomerization.
• Fusion of FAK with CRY2 to create light-sensitive FAK-CRY2 proteins.
• Analysis of downstream signaling events, including SRC activation, paxillin, and p130Cas phosphorylation, in response to blue light.

Main Results:

• OptoFAK enables rapid and reversible activation of FAK and downstream signaling upon blue light exposure, independent of physiological stimuli.
• OptoFAK stimulates SRC, creating a positive feedback loop that enhances FAK activation and substrate phosphorylation in adherent cells.
• In detached or mechanically stressed cells, optoFAK autophosphorylates but shows hampered downstream signaling, suggesting altered substrate accessibility.

Conclusions:

• OptoFAK serves as a valuable tool for studying FAK's role in integrin and growth factor signaling, and in processes like anoikis.
• The system allows for precise temporal and spatial control over FAK activity, aiding research into cell adhesion and mechanical signaling.
• OptoFAK can be utilized as a test system for evaluating kinase inhibitors and understanding their mechanisms of action.