Toolkit Items

Cryptochromes are evolutionarily conserved flavoprotein photoreceptors that sense blue light in multiple organisms. As a protein-domain class, they are used as light-responsive modules in optogenetic systems, while native cryptochromes regulate plant photoresponses and circadian-associated transcriptional programs.

Light-Oxygen-Voltage (LOV) domains are small, light-responsive protein modules found in algae, plants, bacteria, and fungi that function as blue-light sensors controlling cellular responses to light. They are presented as a platform for constructing optogenetic tools that confer photoregulated control of cellular signaling.

The LOV1 domain of Avena sativa phototropin is a PAS-family blue-light-sensing protein domain that binds flavin mononucleotide (FMN). It undergoes a self-contained photocycle in which illumination causes loss of blue-light absorbance through formation of a flavin-cysteinyl adduct, followed by spontaneous dark recovery.

LOV2 is a blue-light-sensing Light-Oxygen-Voltage domain from phototropins, which are multidomain plant photoreceptors containing LOV1, LOV2, and a C-terminal serine/threonine kinase domain. In this native context, light activation of LOV2 induces structural changes that are transmitted to the kinase domain to regulate signaling.

Phot-LOV1 is a LOV1 blue-light receptor domain from the green alga Chlamydomonas reinhardtii. The available evidence indicates that its photocycle has been characterized as a light-responsive protein domain.

VVD is a LOV-domain blue-light photoreceptor from the fungus Neurospora crassa. In the cited optogenetic application, it is used with WC-1 in the FUN-LOV system to create a photon-regulated protein interaction.

The LOV2 domain from Avena sativa (AsLOV2) is a blue-light receptor protein domain. In the cited 2024 study, cofactor exchange with 5-deazaFMN converted AsLOV2 into a photoswitch that forms a light-induced thermodynamically stable adduct and undergoes repeatable photo-induced dark-state recovery.

pYLBI is a single-component blue-light-induced transcription system engineered in Yarrowia lipolytica. It uses a chimeric EL222-VP16 light-responsive transcription factor together with a (C120)5 upstream activation sequence and the minimal promoter CYC102 to drive light-dependent gene expression.