A Proposal for an Electron-Transfer Mechanism of Avian Magnetoreception

TL;DR

This paper proposes a novel avian magnetoreception mechanism involving Cry and IscA1 proteins that facilitates electron transfer to trigger neuronal responses, addressing previous uncertainties in the field.

Contribution

It introduces a combined Cry-IscA1 electron transfer model for bird magnetoreception, integrating structural and magnetic effects to explain sensory transduction.

Findings

Cry-IscA1 complex supports long-range electron transfer

Magnetic effects influence neuronal activity

Proposed mechanism links photoinduced electrons to neuronal responses

Abstract

In spite of many years of research, the mechanism of avian magnetoreception remains a mystery due to its seemingly insurmountable intricacies. Recently Xie and colleagues proposed that IscA1 can act as a protein biocompass due to the measured intrinsic ferromagneticity, and thus named it MagR. However, Meister's calculations showed that the interaction energy of the magnetic moment of IscA1 with Earth's magnetic field is five magnitudes smaller than thermal fluctuation at room temperature. The other long-proposed compass protein is cryptochrome (Cry) with a mechanism of forming singlet-triplet radical pairs. However, this sensory mechanism still has no inferable information transmission routes. We propose a magnetoreception mechanism involving both the Cry and IscA1 proteins, through which photoinduced electrons are transported to redox-regulated ion channels to provoke neuronal responses. The structural features of the Cry-IscA1 complex that make it suitable for long-range electron transfer are discussed and how the magnetic effect leads to neuronal activity is described.