Optical Activation of TrkB Signaling.
Journal of molecular biology
Brain-derived neurotrophic factor (BDNF), via activation of tropomyosin receptor kinase B (TrkB), plays a critical role in neuronal proliferation, differentiation, survival, and death. Dysregulation of TrkB signaling is implicated in neurodegenerative disorders and cancers. Precise activation of TrkB signaling with spatial and temporal resolution is greatly desired to study the dynamic nature of TrkB signaling and its role in related diseases. Here we develop different optogenetic approaches that use light to activate TrkB signaling. Utilizing the photosensitive protein Arabidopsis thaliana cryptochrome 2 (CRY2), the light-inducible homo-interaction of the intracellular domain of TrkB (iTrkB) in the cytosol or on the plasma membrane is able to induce the activation of downstream MAPK/ERK and PI3K/Akt signaling as well as the neurite outgrowth of PC12 cells. Moreover, we prove that such strategies are generalizable to other optical homo-dimerizers by demonstrating the optical TrkB activation based on the light-oxygen-voltage domain of aureochrome 1 from Vaucheria frigida. The results open up new possibilities of many other optical platforms to activate TrkB signaling to fulfill customized needs. By comparing all the different strategies, we find that the CRY2-integrated approach to achieve light-induced cell membrane recruitment and homo-interaction of iTrkB is most efficient in activating TrkB signaling. The optogenetic strategies presented are promising tools to investigate BDNF/TrkB signaling with tight spatial and temporal control.
View details for DOI 10.1016/j.jmb.2020.05.002
View details for PubMedID 32422149
Construction of Light-Activated Neurotrophin Receptors Using the Improved Light-Induced Dimerizer (iLID).
Journal of molecular biology
Receptor tyrosine kinases (RTKs) play crucial roles in human health, and their misregulation is implicated in disorders ranging from neurodegenerative diseases to cancers. The highly conserved mechanism of activation of RTKs makes them especially appealing candidates for control via optogenetic dimerization methods. This work offers a strategy for using the improved Light-Induced Dimer (iLID) system with a constructed tandem-dimer of its binding partner nano (tdnano) to build light-activatable versions of RTKs. In the absence of light, the iLID-RTK is cytosolic, monomeric and inactive. Under blue light, the iLID + tdnano system recruits two copies of iLID-RTK to tdnano, dimerizing and activating the RTK. We demonstrate that iLID opto-iTrkA and opto-iTrkB are capable of reproducing downstream ERK and Akt signaling only in the presence of tdnano. We further show with our opto-iTrkA that the system is compatible with multi-day and population-level activation of TrkA in PC12 cells. By leveraging genetic targeting of tdnano, we achieve RTK activation at a specific subcellular location even with whole-cell illumination, allowing us to confidently probe the impact of context on signaling outcome.
View details for DOI 10.1016/j.jmb.2020.04.018
View details for PubMedID 32335036
Developing Nanoelectrodes into Robust Electrophysiological Tools for Accurate and Parallel Recording of Action Potentials from Single Cells
CELL PRESS. 2020: 28A
View details for Web of Science ID 000513023200135
Light-Inducible Generation of Membrane Curvature in Live Cells with Engineered BAR Domain Proteins.
ACS synthetic biology
Nanoscale membrane curvature is now understood to play an active role in essential cellular processes such as endocytosis, exocytosis, and actin dynamics. Previous studies have shown that membrane curvature can directly affect protein function and intracellular signaling. However, few methods are able to precisely manipulate membrane curvature in live cells. Here, we report the development of a new method of generating nanoscale membrane curvature in live cells that is controllable, reversible, and capable of precise spatial and temporal manipulation. For this purpose, we make use of Bin/Amphiphysin/Rvs (BAR) domain proteins, a family of well-studied membrane-remodeling and membrane-sculpting proteins. Specifically, we engineered two optogenetic systems, opto-FBAR and opto-IBAR, that allow light-inducible formation of positive and negative membrane curvature, respectively. Using opto-FBAR, blue light activation results in the formation of tubular membrane invaginations (positive curvature), controllable down to the subcellular level. Using opto-IBAR, blue light illumination results in the formation of membrane protrusions or filopodia (negative curvature). These systems present a novel approach for light-inducible manipulation of nanoscale membrane curvature in live cells.
View details for DOI 10.1021/acssynbio.9b00516
View details for PubMedID 32212723
Direct beta-Selective Hydrocarboxylation of Styrenes with CO2 Enabled by Continuous Flow Photoredox Catalysis
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2017; 139 (40): 13969–72
The direct β-selective hydrocarboxylation of styrenes under atmospheric pressure of CO2 has been developed using photoredox catalysis in continuous flow. The scope of this methodology was demonstrated with a range of functionalized terminal styrenes, as well as α-substituted and β-substituted styrenes.
View details for DOI 10.1021/jacs.7b05942
View details for Web of Science ID 000413057100002
View details for PubMedID 28953365