CL6mN: Rationally Designed Optogenetic Photoswitches with Tunable Dissociation Dynamics

Area of Science:

• Optogenetics
• Molecular Biology
• Biotechnology

Background:

• Optogenetics enables precise control of biological processes using light-sensitive proteins.
• The cryptochrome 2 photolyase homology region (Cry2PHR) is a key building block for optogenetic tools.
• Existing Cry2PHR-based tools can be limited by cluster stability and tunability.

Purpose of the Study:

• To design and characterize novel optogenetic photoswitches based on Cry2PHR with improved clustering properties.
• To engineer photoswitches with tunable dissociation half-lives for enhanced temporal control.
• To demonstrate the utility of these new photoswitches in mammalian cell systems.

Main Methods:

• Rational design and mutagenesis of Cry2PHR-based proteins (CL6mN variants) by modifying C-terminal PPPAP motifs.
• Characterization of light-induced clustering dynamics, including dissociation half-lives.
• Demonstration of optogenetic activation of RhoA signaling in mammalian cells using the developed photoswitches.

Main Results:

• Engineered CL6mN proteins exhibit efficient, blue-light-dependent clustering.
• CL6mN clusters display significantly longer dissociation half-lives compared to wild-type Cry2PHR.
• Dissociation half-lives are tunable by altering the number of PPPAP motifs, with up to a 6-fold increase observed.
• The CL6mN system is compatible with other Cry2-based photoswitches for complex optogenetic circuit design.

Conclusions:

• Novel Cry2PHR-based photoswitches (CL6mN) offer enhanced and tunable light-induced clustering.
• These photoswitches provide greater control over optogenetic experiments due to increased cluster stability.
• The developed tools are versatile and applicable for optogenetic manipulation in mammalian cells, including pathway activation.