Curated Optogenetic Publication Database

Abstract: Regulated secretion is critical for diverse biological processes ranging from immune and endocrine signaling to synaptic transmission. Botulinum and tetanus neurotoxins, which specifically proteolyze vesicle fusion proteins involved in regulated secretion, have been widely used as experimental tools to block these processes. Genetic expression of these toxins in the nervous system has been a powerful approach for disrupting neurotransmitter release within defined circuitry, but their current utility in the brain and elsewhere remains limited by lack of spatial and temporal control. Here we engineered botulinum neurotoxin B so that it can be activated with blue light. We demonstrate the utility of this approach for inducibly disrupting excitatory neurotransmission, providing a first-in-class optogenetic tool for persistent, light-triggered synaptic inhibition. In addition to blocking neurotransmitter release, this approach will have broad utility for conditionally disrupting regulated secretion of diverse bioactive molecules, including neuropeptides, neuromodulators, hormones, and immune molecules. VIDEO ABSTRACT.

Abstract: The molecular composition of the postsynaptic membrane is sculpted by synaptic activity. During synaptic plasticity at excitatory synapses, numerous structural, signaling, and receptor molecules concentrate at the postsynaptic density (PSD) to regulate synaptic strength. We developed an approach that uses light to tune the abundance of specific molecules in the PSD. We used this approach to investigate the relationship between the number of AMPA-type glutamate receptors in the PSD and synaptic strength. Surprisingly, adding more AMPA receptors to excitatory contacts had little effect on synaptic strength. Instead, we observed increased excitatory input through the apparent addition of new functional sites. Our data support a model where adding AMPA receptors is sufficient to activate synapses that had few receptors to begin with, but that additional remodeling events are required to strengthen established synapses. More broadly, this approach introduces the precise spatiotemporal control of optogenetics to the molecular control of synaptic function.

Abstract: Optical control of protein interactions has emerged as a powerful experimental paradigm for manipulating and studying various cellular processes. Tools are now available for controlling a number of cellular functions, but some fundamental processes, such as protein secretion, have been difficult to engineer using current optical tools. Here we use UVR8, a plant photoreceptor protein that forms photolabile homodimers, to engineer the first light-triggered protein secretion system. UVR8 fusion proteins were conditionally sequestered in the endoplasmic reticulum, and a brief pulse of light triggered robust forward trafficking through the secretory pathway to the plasma membrane. UVR8 was not responsive to excitation light used to image cyan, green, or red fluorescent protein variants, allowing multicolor visualization of cellular markers and secreted protein cargo as it traverses the cellular secretory pathway. We implemented this novel tool in neurons to demonstrate restricted, local trafficking of secretory cargo near dendritic branch points.