title: Subcellular optogenetic inhibition of G proteins generates signaling gradients and cell migration.
abstract: Cells sense gradients of extracellular cues and generate polarized responses such as cell migration and neurite initiation. There is static information on the intracellular signaling molecules involved in these responses, but how they dynamically orchestrate polarized cell behaviors is not well understood. A limitation has been the lack of methods to exert spatial and temporal control over specific signaling molecules inside a living cell. Here we introduce optogenetic tools that act downstream of native G protein-coupled receptor (GPCRs) and provide direct control over the activity of endogenous heterotrimeric G protein subunits. Light-triggered recruitment of a truncated regulator of G protein signaling (RGS) protein or a Gβγ-sequestering domain to a selected region on the plasma membrane results in localized inhibition of G protein signaling. In immune cells exposed to spatially uniform chemoattractants, these optogenetic tools allow us to create reversible gradients of signaling activity. Migratory responses generated by this approach show that a gradient of active G protein αi and βγ subunits is sufficient to generate directed cell migration. They also provide the most direct evidence so for a global inhibition pathway triggered by Gi signaling in directional sensing and adaptation. These optogenetic tools can be applied to interrogate the mechanistic basis of other GPCR-modulated cellular functions.
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: O'Neill
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110 gautam@wustl.edu.
authors.forename: N
authors.initials: N
authors.lastname: Gautam
mesh_terms: D000818:Animals; D002633:Chemotaxis; D056931:Cryptochromes / Q000502:physiology; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000502:physiology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000378:metabolism; D051379:Mice; D062308:Optogenetics; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport; D015398:Signal Transduction
chemical_list: C538966:CRY2 protein, human; D056931:Cryptochromes; D007295:Inositol Phosphates; D021122:Protein Subunits; D006160:Guanosine Triphosphate; C496567:GRK2 protein, human; D054769:G-Protein-Coupled Receptor Kinase 2; D019204:GTP-Binding Proteins