Directly light-regulated binding of RGS-LOV photoreceptors to anionic membrane phospholipids

作者:Glantz Spencer T; Berlew Erin E; Jaber Zaynab; Schuster Benjamin S; Gardner Kevin H; Chow Brian Y*
来源:Proceedings of the National Academy of Sciences, 2018, 115(33): E7720-E7727.
DOI:10.1073/pnas.1802832115

摘要

We report natural light-oxygen-voltage (LOV) photoreceptors with a blue light-switched, high-affinity (K-D similar to 10(-7) M), and direct electrostatic interaction with anionic phospholipids. Membrane localization of one such photoreceptor, BcLOV4 from Botrytis cinerea, is directly coupled to its flavin photocycle, and is mediated by a polybasic amphipathic helix in the linker region between the LOV sensor and its C-terminal domain of unknown function (DUF), as revealed through a combination of bioinformatics, computational protein modeling, structure-function studies, and optogenetic assays in yeast and mammalian cell line expression systems. In model systems, BcLOV4 rapidly translocates from the cytosol to plasma membrane (similar to 1 second). The reversible electrostatic interaction is nonselective among anionic phospholipids, exhibiting binding strengths dependent on the total anionic content of the membrane without preference for a specific headgroup. The in vitro and cellular responses were also observed with a BcLOV4 homolog and thus are likely to be general across the dikarya LOV class, whose members are associated with regulator of G-protein signaling (RGS) domains. Natural photoreceptors are not previously known to directly associate with membrane phospholipids in a light-dependent manner, and thus this work establishes both a photosensory signal transmission mode and a single-component optogenetic tool with rapid membrane localization kinetics that approaches the diffusion limit.

  • 出版日期2018-8-14