Optogenetic approaches to cell migration and beyond

Abstract

Optogenetics, the use of genetically encoded tools to control protein function with light, can generate localized changes in signaling within living cells and animals. For years it has been focused on channel proteins for neurobiology, but has recently expanded to cover many different types of proteins, using a broad array of different protein engineering approaches. These methods have largely been directed at proteins involved in motility, cytoskeletal regulation and gene expression. This review provides a survey of non-channel proteins that have been engineered for optogenetics. Existing molecules are used to illustrate the advantages and disadvantages of the many imaginative new approaches that the reader can use to create light-controlled proteins.

Figure 1

Steric blocking of active sites. A. LOV blocks the target’s active site when the Ja helix is tightly coiled, but when Ja unwinds to generate a long tether, the active site is exposed. B. A peptide that affects endogenous proteins can be appended to the Ja helix, where it is sterically blocked from interactions until LOV is irradiated. C. Dimerization of DRONPA across the active site of the targeted protein blocks interaction with ligands until irradiation disrupts dimerization.

Figure 2

Optogenetic Control by Dimerization. A. The optoFGFR1 system for dimerization-mediated activation of receptor tyrosine kinase (RTK) signaling[49]. B. The TULIP system for “dimerization”-mediated recruitment. C. Light-induced dimerization for targeting protein to sites of action, including the plasma membrane and organelles.. This has been driven by Phy/PIF, Cry/CIB and FKF1/GIGANTEA. D. Gene expression through the dimerization of UVR8 and COP1. COP1 is expressed as a fusion linked to a DNA binding domain (DB), while URV8 is fused to a transcriptional activation domain (TA). This has also been driven by PhyB, LOV and Cry.

Figure 3

Other designs for optogenetic control. A. Schematic representation of the LARIAT system. B. Light-induced clustering of CRY2. C. Light induced allosteric regulation of enzyme activity [21, 22, 40].