Curated Optogenetic Publication Database

Search precisely and efficiently by using the advantage of the hand-assigned publication tags that allow you to search for papers involving a specific trait, e.g. a particular optogenetic switch or a host organism.

Showing 1 - 2 of 2 results

A photoreceptor-based hydrogel with red light-responsive reversible sol-gel transition as transient cellular matrix.

red PhyB/PIF6 in vitro Extracellular optogenetics
bioRxiv, 23 May 2023 DOI: 10.1101/2023.04.04.535523 Link to full text
Abstract: Hydrogels with adjustable mechanical properties have been engineered as matrices for mammalian cells and allow the dynamic, mechano-responsive manipulation of cell fate and function. Recent research yielded hydrogels, where biological photoreceptors translated optical signals into a reversible and adjustable change in hydrogel mechanics. While their initial application provided important insights into mechanobiology, broader implementation is limited by a small dynamic range of addressable stiffness. Here, we overcome this limitation by developing a photoreceptor-based hydrogel with reversibly adjustable stiffness from 800 Pa to the sol state. The hydrogel is based on star-shaped polyethylene glycol, functionalized with the red/far-red light photoreceptor phytochrome B (PhyB), or phytochrome-interacting factor 6 (PIF6). Upon illumination with red light, PhyB heterodimerizes with PIF6, thus crosslinking the polymers and resulting in gelation. However, upon illumination with far-red light, the proteins dissociate and trigger a complete gel-to-sol transition. We comprehensively characterize the hydrogel’s light-responsive mechanical properties and apply it as reversible extracellular matrix for the spatiotemporally controlled deposition of mammalian cells within a microfluidic chip. We anticipate that this technology will open new avenues for the site- and time-specific positioning of cells and will contribute to overcome spatial restrictions.

Opto-APC: Engineering of cells that display phytochrome B on their surface for optogenetic studies of cell-cell interactions.

red PhyB/PIF6 HEK293T Jurkat Raji Control of cell-cell / cell-material interactions Extracellular optogenetics
Front Mol Biosci, 20 Feb 2023 DOI: 10.3389/fmolb.2023.1143274 Link to full text
Abstract: The kinetics of a ligand-receptor interaction determine the responses of the receptor-expressing cell. One approach to experimentally and reversibly change this kinetics on demand is optogenetics. We have previously developed a system in which the interaction of a modified receptor with an engineered ligand can be controlled by light. In this system the ligand is a soluble Phytochrome B (PhyB) tetramer and the receptor is fused to a mutated PhyB-interacting factor (PIFS). However, often the natural ligand is not soluble, but expressed as a membrane protein on another cell. This allows ligand-receptor interactions in two dimensions. Here, we developed a strategy to generate cells that display PhyB as a membrane-bound protein by expressing the SpyCatcher fused to a transmembrane domain in HEK-293T cells and covalently coupling purified PhyB-SpyTag to these cells. As proof-of-principle, we use Jurkat T cells that express a GFP-PIFS-T cell receptor and show that these cells can be stimulated by the PhyB-coupled HEK-293T cells in a light dependent manner. Thus, we call the PhyB-coupled cells opto-antigen presenting cells (opto-APCs). Our work expands the toolbox of optogenetic technologies, allowing two-dimensional ligand-receptor interactions to be controlled by light.
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