Fig. 2.

Neuronal modulation using radio- or magnetogenetics. A viral vector can be used to deliver the 2 components required for radio- or magnetogenetics, GFP-ferritin and anti-GFP-TRPV1, to the target cell. GFP-ferritin is a ubiquitous iron storage protein that has been modified by addition of green fluorescent protein (GFP), whereas anti-GFP-TRPV1 is a transient receptor potential vanilloid 1 (TRPV1) cation channel modified by addition of a small anti-GFP domain. Once expressed by the cell, the GFP-ferritin self-assembles into a shell and sequesters iron ions in a nanoparticle. TRPV1 subunits self-assemble on the cell membrane. The GFP tag of GFP-ferritin will bind to the anti-GFP domain of the first extracellular loop of the modified TRPV1 channel, thus tethering GFP-ferritin to the modified TRPV1 channel. Application of a radio frequency or a magnetic field will transfer energy to the iron oxide nanoparticles within the GFP-ferritin and trigger ion channel opening, Na⁺ and Ca²⁺ entry into the cell, and depolarization.