Proposed three-phenylalanine motif involved in magnetoreception signaling of an Actinopterygii protein expressed in mammalian cells

Studies at the cellular and molecular level of magnetoreception – sensing and responding to magnetic fields – is a relatively new research area. As it appears that different mechanisms of magnetoreception in animals evolved from different origins, many questions about the mechanisms remain left open. Here we present new information regarding the Electromagnetic Perceptive Gene (EPG) from Kryptopterus vitreolus that may serve as part of the foundation to understanding and applying magnetoreception. Using HaloTag coupled with fluorescent ligands and phosphatidylinositol specific phospholipase C (PI-PLC) we show that EPG is associated to the membrane via glycosylphosphatidylinositol (GPI) anchor. EPG’s function of increasing intracellular calcium was also used to generate an assay using GCaMP6m to observe the function of EPG and to compare its function with homologous proteins. It was also revealed that EPG relies on a motif of three phenylalanine residues in order to function – stably swapping these residues using site directed mutagenesis resulted in a loss of function in EPG. This information not only expands upon our current understanding of magnetoreception but may provide a foundation and template to continue characterizing and discovering more within the field. Graphical Abstract In Brief EPG is a magnetoreceptive GPI anchored protein. Critical to its function is a three-phenylalanine motif which allows EPG to sense and respond to EMF. When expressed in mammalian cell, an increase in intracellular calcium is observed using GCaMP6m. This work represents progress towards understanding magnetoreception for use in future technologies. Highlights EPG is associated to the cell membrane via glycosylphosphatidylinositol anchoring In mammalian cells, EPG increases intracellular calcium upon EMF stimulation Homologs of EPG from the uPAR/Ly6 family show different responses to EMF A three-phenylalanine motif in EPG is critical to its magnetoreceptive ability