Oxygen-sensing enzymes in plants and animals Emily Flashman
University of Oxford, United Kingdom emily.flashman@biology.ox.ac.uk.
All aerobic organisms need oxygen to survive and must have homeostatic mechanisms in place to adapt to a reduction in oxygen availability (hypoxia). In animals, these adaptation responses are driven by the Hypoxia- Inducible transcription Factors (HIF); HIF stability is controlled by oxygen-dependent HIF hydroxylase enyzmes whose kinetic properties control rates of reaction with oxygen, conferring a physiologically important sensitivity to the response to hypoxia. Plants are also susceptible to metabolic stress when oxygen availability is limiting. This can occur when plants are flooded or in certain developmental states. In a mechanism which is distinct yet parallel to the well-characterised HIF-mediated hypoxic response in animals, plants respond to hypoxia through the action of transcription factors that upregulate the expression of adaptive genes. The stability of these transcription factors is regulated by oxygen-sensing Plant Cysteine Oxidases (PCOs). I will describe our work defining how PCOs act on plant transcription factors to trigger their degradation in an oxygen-sensitive manner, as well as our efforts to engineer the activity of these enzymes to prolong the plant hypoxic response and improve flood tolerance. I’ll also describe how a homologous cysteine dioxygenase was revealed to act as a novel oxygen- sensing enzyme in humans, indicating that thiol dioxygenases may be an evolutionarily conserved mechanism of sensing and responding to reduced oxygen availability.
K01
© The Author(s), 2023
Made with FlippingBook Learn more on our blog