Tag:degron(B-LID) consists of the LOV2 domain of the Avena sativa Phototropin 1 (PT1) gene, including the C-terminal α-helix and LOV core domain, with an RRRG degron sequence fused to its C-terminal end. In addition, the LOV2 domain lacks the three most C-terminal amino acids of the full-length sequence and carries a I532A amino acid substitution. When fused to the C-terminal end of a protein of interest, Tag:degron(B-LID) can be used to regulate the stability of the tagged protein in a blue-light dependent manner. In the dark, the LOV core domain interacts with the α-helix, resulting in a closed conformation in which the RRRG degron sequence is inaccessible. Upon illumination with blue light, the α-helix unfolds and dissociates from the LOV core domain, exposing the RRRG degron sequence and inducing proteasome-mediated degradation of the Tag:degron(B-LID) sequence and the protein of interest to which it is fused (PMID:24180414).