An optogenetic system for interrogating the temporal dynamics of Akt

Area of Science:

• Molecular Biology
• Cell Signaling
• Optogenetics

Background:

• The serine/threonine kinase Akt regulates vital cellular processes.
• Precise spatiotemporal control of Akt activity is essential but challenging.
• Existing methods lack fine-tuned temporal regulation of Akt signaling.

Purpose of the Study:

• To develop a photo-activatable Akt (PA-Akt) system for light-inducible control of Akt activity.
• To investigate the role of temporal Akt activity patterns in regulating downstream cellular functions.
• To establish a general framework for quantitative manipulation of biomolecular dynamics using optogenetics and computational modeling.

Main Methods:

• Constructed a PA-Akt system using the Arabidopsis thaliana cryptochrome2 (CRY2) and CIB1 light-inducible interaction module.
• Fused Akt to a minimal light-sensitive domain of CRY2 (CRY2-Akt) for reversible light activation.
• Developed a computational model to quantitatively predict and control CRY2-Akt activation dynamics.

Main Results:

• Demonstrated reversible light-induced activation of CRY2-Akt within minutes in a physiological dynamic range.
• Showcased specific regulation of downstream molecules and inducible biological functions by PA-Akt.
• Provided evidence that temporal patterns of Akt activity are critical for regulating the expression of Atrogin-1, a gene involved in muscle atrophy, via the Akt-FoxO pathway.

Conclusions:

• The PA-Akt system offers precise spatiotemporal control over Akt signaling through light.
• Temporal dynamics of Akt activity significantly influence downstream cellular outcomes, such as muscle atrophy gene expression.
• Optogenetic tools combined with computational modeling provide a powerful generalizable approach for studying and manipulating biomolecular temporal dynamics.