1,757 research outputs found
Optogenetic Modulation of TrkB Signaling in the Mouse Brain
No full textOptogenetic activation of receptors has advantages compared with chemical or ligand treatment because of its high spatial and temporal precision. Especially in the brain, the use of a genetically encoded light-tunable receptor is superior to direct infusion or systemic drug treatment. We applied light-activatable TrkB receptors in the mouse brain with reduced basal activity by incorporating Cry2PHR mutant, Opto-cytTrkB(E281A). Upon AAV mediated gene delivery, this form was expressed at sufficient levels in the mouse hippocampus (HPC) and medial entorhinal cortex (MEC) retaining normal canonical signal transduction by the blue light stimulus, even by delivery of noninvasive LED light on the mouse head. Within target cells, where its expression was driven by a cell type-specific promoter, Opto-cytTrkB(E281A)-mediated TrkB signaling could be controlled by adjusting light-stimulating conditions. We further demonstrated that Opto-cytTrkB(E281A) could locally induce TrkB signaling in axon terminals in the MEC-HPC. In summary, Opto-cytTrkB(E281A) will be useful for elucidating time- and region-specific roles of TrkB signaling ranging from cellular function to neural circuit mechanisms. © 2020 The Author(s). Published by Elsevier Ltd.11Nsciescopu
Optogenetic tools for dissecting complex intracellular signaling pathways
No full text© 2020 Elsevier Inc. All rights reserved. Intracellular signaling forms complicated networks that involve dynamic alterations of the protein-protein interactions occurring inside a cell. To dissect these complex networks, light-inducible optogenetic technologies have offered a novel approach for modulating the function of intracellular machineries in space and time. Optogenetic approaches combine genetic and optical methods to initiate and control protein functions within live cells. In this review, we provide an overview of the optical strategies that can be used to manipulate intracellular signaling proteins and secondary messengers at the molecular level. We briefly address how an optogenetic actuator can be engineered to enhance homo- or hetero-interactions, survey various optical tools and targeting strategies for controlling cell-signaling pathways, examine their extension to in vivo systems and discuss the future prospects for the field11Nsciescopu
Cas13 단백질의 활성 조절을 통한 RNA 발현 조절 또는 편집 방법
No full textThe present invention relates to a RNA expression modulating or editing method through chemical or optogenetic regulation of Cas13 protein activity. Specifically, in order to regulate the activity of Cas13 in the CRISPR-Cas13 system, a fragment of the Cas13 protein was generated to enable recombination, and a chemogenetically or optogenetically bindable protein was linked to each fragment. And, it was confirmed that the Cas13 protein can be activated by treatment of a low molecular weight compound or irradiation of light. Accordingly, the method of the present invention can be effectively used for disease treatment by regulating RNA expression or editing RNA mutations related to disease
Synergistic Ensemble of Optogenetic Actuators and Dynamic Indicators in Cell Biology.
No full textDiscovery of the naturally evolved fluorescent proteins and their genetically engineered biosensors have enormously contributed to current bio-imaging techniques. These reporters to trace dynamic changes of intracellular protein activities have continuously transformed according to the various demands in biological studies. Along with that, light-inducible optogenetic technologies have offered scientists to perturb, control and analyze the function of intracellular machineries in spatio-temporal manner. In this review, we present an overview of the molecular strategies that have been exploited for producing genetically encoded protein reporters and various optogenetic modules. Finally, in particular, we discuss the current efforts for combined use of these reporters and optogenetic modules as a powerful tactic for the control and imaging of signaling events in cells and tissues. (c) The Korean Society for Molecular and Cellular Biology. All rights reserved.11Nsciekc
Switch-of-function mutants based on morphology classification of Ras superfamily small GTPases
No full textSignaling proteins from the same family can have markedly different roles in a given cellular context. Here, we show that expression of one hundred constitutively active human small GTPases induced cell morphologies that fell into nine distinct classes. We developed an algorithm for pairs of classes that predicted amino acid positions that can be exchanged to create mutants with switched functionality. The algorithm was validated by creating switch-of-function mutants for Rac1, CDC42, H-Ras, RalA, Rap2B, and R-Ras3. Contrary to expectations, the relevant residues were mostly outside known interaction surfaces and were structurally far apart from each other. Our study shows that specificity in protein families can be explored by combining genome-wide experimental functional classification with the creation of switch-of-function mutants
Optogenetic toolkit reveals the role of Ca2+ sparklets in coordinated cell migration
No full textCell migration is controlled by various Ca2+ signals. Local Ca2+ signals, in particular, have been identified as versatile modulators of cell migration because of their spatiotemporal diversity. However, little is known about how local Ca2+ signals coordinate between the front and rear regions in directionally migrating cells. Here, we elucidate the spatial role of local Ca2+ signals in directed cell migration through combinatorial application of an optogenetic toolkit. An optically guided cell migration approach revealed the existence of Ca2+ sparklets mediated by L-type voltage-dependent Ca2+ channels in the rear part of migrating cells. Notably, we found that this locally concentrated Ca2+ influx acts as an essential transducer in establishing a global front-to-rear increasing Ca2+ gradient. This asymmetrical Ca2+ gradient is crucial for maintaining front-rear morphological polarity by restricting spontaneous lamellipodia formation in the rear part of migrating cells. Collectively, our findings demonstrate a clear link between local Ca2+ sparklets and front-rear coordination during directed cell migration.1991Nsciescopu
Revisiting the Role of TGFβ Receptor Internalization for Smad Signaling: It is Not Required in Optogenetic TGFβ Signaling Systems
No full textEndocytosis is an important process by which many signaling receptors reach their intracellular effectors. Accumulating evidence suggests that internalized receptors play critical roles in triggering cellular signaling, including transforming growth factor β (TGFβ) signaling. Despite intensive studies on the TGFβ pathway over the last decades, the necessity of TGFβ receptor endocytosis for downstream TGFβ signaling responses is a subject of debate. In this study, mathematical modeling and synthetic biology approaches are combined to re-evaluate whether TGFβ receptor internalization is indispensable for inducing Smad signaling. It is found that optogenetic systems with plasma membrane-tethered TGFβ receptors can induce fast and sustained Smad2 activation upon light stimulations. Modeling analysis suggests that endocytosis is precluded for the membrane-anchored optogenetic TGFβ receptors. Therefore, this study provides new evidence to support that TGFβ receptor internalization is not required for Smad2 activation
Optogenetic protein clustering through fluorescent protein tagging and extension of CRY2
No full textProtein homo-oligomerization is an important molecular mechanism in many biological processes. Therefore, the ability to control protein homo-oligomerization allows the manipulation and interrogation of numerous cellular events. To achieve this, cryptochrome 2 (CRY2) from Arabidopsis thaliana has been recently utilized for blue light-dependent spatiotemporal control of protein homo-oligomerization. However, limited knowledge on molecular characteristics of CRY2 obscures its widespread applications. Here, we identify important determinants for efficient cryptochrome 2 clustering and introduce a new CRY2 module, named ''CRY2clust'', to induce rapid and efficient homo-oligomerization of target proteins by employing diverse fluorescent proteins and an extremely short peptide. Furthermore, we demonstrate advancement and versatility of CRY2clust by comparing against previously reported optogenetic tools. Our work not only expands the optogenetic clustering toolbox but also provides a guideline for designing CRY2-based new optogenetic modules. © 2017 The Author(s)1461Nsciescopu
Programmable RNA base editing with photoactivatable CRISPR-Cas13
No full textAbstract CRISPR-Cas13 is widely used for programmable RNA interference, imaging, and editing. In this study, we develop a light-inducible Cas13 system called paCas13 by fusing Magnet with fragment pairs. The most effective split site, N351/C350, was identified and found to exhibit a low background and high inducibility. We observed significant light-induced perturbation of endogenous transcripts by paCas13. We further present a light-inducible base-editing system, herein called the padCas13 editor, by fusing ADAR2 to catalytically inactive paCas13 fragments. The padCas13 editor enabled reversible RNA editing under light and was effective in editing A-to-I and C-to-U RNA bases, targeting disease-relevant transcripts, and fine-tuning endogenous transcripts in mammalian cells in vitro. The padCas13 editor was also used to adjust post-translational modifications and demonstrated the ability to activate target transcripts in a mouse model in vivo. We therefore present a light-inducible RNA-modulating technique based on CRISPR-Cas13 that enables target RNAs to be diversely manipulated in vitro and in vivo, including through RNA degradation and base editing. The approach using the paCas13 system can be broadly applicable to manipulating RNA in various disease states and physiological processes, offering potential additional avenues for research and therapeutic development
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