Light controls protein localization through phytochrome-mediated alternative promoter selection ($)

Previous studies have shown that some genes use multiple promoters, but the extent to which this occurs has not been fully resolved. Ushijima et al. showed widespread phytochrome-mediated differential promoter use in response to light. They identified more than 2000 genes with light-dependent alternative promoter selection, most affecting the length of the N-terminus of the protein. From these, they verified nearly 400 in which the different protein isoforms localize differentially within the cell. They further investigate how this affects glycerate kinase (GLYK), which they show is expressed as a longer, plastid-localized protein in the light, but a shorter, cytosolic protein in darkness, providing an cytoplasmic photorespiratory bypass mechanism. (Summary by Mary Williams)  Cell 10.1016/j.cell.2017.10.018