Recent developments of genetically encoded optical sensors for cell biology

Abstract

Optical sensors are powerful tools for live cell research as they permit to follow the location, concentration changes or activities of key cellular players such as lipids, ions and enzymes. Most of the current sensor probes are based on fluorescence which provides great spatial and temporal precision provided that high-end microscopy is used and that the timescale of the event of interest fits the response time of the sensor. Many of the sensors developed in the past 20 years are genetically encoded. There is a diversity of designs leading to simple or sometimes complicated applications for the use in live cells. Genetically encoded sensors began to emerge after the discovery of fluorescent proteins, engineering of their improved optical properties and the manipulation of their structure through application of circular permutation. In this review, we will describe a variety of genetically encoded biosensor concepts, including those for intensiometric and ratiometric sensors based on single fluorescent proteins, Forster resonance energy transfer-based sensors, sensors utilising bioluminescence, sensors using self-labelling SNAP- and CLIP-tags, and finally tetracysteine-based sensors. We focus on the newer developments and discuss the current approaches and techniques for design and application. This will demonstrate the power of using optical sensors in cell biology and will help opening the field to more systematic applications in the future.

Green fluorescent proteins induce oxidative stress in cells: A worrisome new wrinkle in the application of the GFP reporter system to biological systems?

“…Importantly, both O 2 •− and H 2 O 2 induce redox signaling mechanisms, leading to altered gene expression of cell regulatory proteins involved in cell proliferation, cell differentiation, and cell death [7], [8], [9], [10]. Thus, the findings reported in this paper could have a major influence on the interpretation of results obtained from numerous studies that routinely use fluorescent protein tags [11], [12], [13].…”

Optogenetic Approaches to Drug Discovery in Neuroscience and Beyond

“…Recent reviews have discussed optogenetic actuators [10, 11] and reporters [12-14] in detail. In this review, we discuss how optogenetics can facilitate target discovery and validation, high-throughput screening, functional phenotypic assays, safety pharmacology and toxicity, and patient stratification for clinical trials.…”

“…Fluorescently labeled toxins with state-dependent binding probe activation of native K v 2.1 ion channels [73]. FRET-based reporters can probe activation of specific kinases, GPCRs, and other targets [13, 14]. With these tools, one can perform target-based screens in native cells.…”

Encapsulated Optically Responsive Cell Systems: Toward Smart Implants in Biomedicine

“…Genetically encoded (GE) sensor generation relies on the translation of a nucleic acid sequence and the incorporation into living cells by transfection, viral transduction of plasmid DNA, or electroporation. Over recent decades, the huge development of GE sensors has enabled real‐time observation and quantification of dynamic events with exquisite spatial and temporal resolution, in both live cells and animals . Given that those sensors may be expressed in living cells, they are also, in principle, suitable for encapsulation purposes, largely increasing the repertoire of their biomedical applications (see Section ).…”