A cellular brake on blood pigment protects aging cells
The regulation of haem, the iron-containing molecule that gives red blood cells their oxygen-carrying ability, is tighter than previously thought. A new Science study reveals a mitochondrial protein that acts as a brake on haem production. When that brake fails, toxic byproducts accumulate.
Haem is essential for oxygen transport, but too much is toxic. Cells must therefore carefully control how much they produce. How that internal regulation works inside mitochondria, the cell’s energy-generating compartments, was until now only partially understood.
The study, published in Science, identifies an adaptor protein that functions as a feedback switch: it connects a mitochondrial proteolytic enzyme (one that breaks down proteins) to the first enzyme in the haem biosynthesis chain. When sufficient haem is present, this first enzyme is degraded via that proteolytic route. The cell thus regulates itself.
What goes wrong with aging?
Mitochondrial regulatory systems deteriorate with age. If proteolytic control of haem production becomes less efficient, intermediates in the haem synthesis pathway can accumulate. Some of those intermediates are toxic to cells. In principle, such accumulation contributes to oxidative damage, one of the recognised mechanisms of cellular aging. The authors describe this as a newly identified regulatory node, but the direct link to aging in humans remains speculative and requires further investigation.
Why this node is worth watching
Protein degradation as a regulatory mechanism inside mitochondria is a relatively new research area. Disruptions in this system have been linked to neurodegenerative conditions and to the general decline of mitochondrial quality control with age. This specific regulatory node is therefore a potential target for future interventions, though that stage remains distant.
Want to research this yourself?
Search for example:
- mitochondrial proteolytic regulation
- heme biosynthesis feedback mechanism
- mitochondrial quality control aging