Scientists Unveil Mitochondrial Transport Mystery

Scientists working in a laboratory with microscopes and test tubes

Your cells have been running a high-stakes smuggling operation for decades, and scientists just caught the courier.

Quick Take

Coenzyme A (CoA), made from vitamin B5, sits mostly inside mitochondria even though cells build it outside those “power plants.”
Yale researchers identified two mitochondrial transporters, SLC25A42 and SLC25A16, that bring CoA inside.
A new mass spectrometry workflow mapped dozens of CoA “versions,” solving a technical roadblock that kept the mystery alive.
The discovery strengthens the case that some mitochondrial and metabolic diseases may hinge on CoA delivery, not just CoA production.

The CoA Paradox That Never Made Sense on Paper

CoA is one of those molecules biochemistry can’t live without: it helps run core fuel cycles and supports the chemical trades that keep tissues functioning. The paradox was blunt. Cells assemble CoA from vitamin B5 in the cytosol, yet roughly 95% of CoA is found inside mitochondria, where energy metabolism hums. That mismatch forced one conclusion: mitochondria must import CoA. The field just didn’t know how.

Researchers at Yale School of Medicine, led by Hongying Shen, pushed straight through the bottleneck that made the question so stubborn. CoA rarely exists as a single, tidy substance; it shows up as a sprawling set of chemically related conjugates. When you can’t reliably measure the full family, you can’t convincingly prove what moves where. Shen’s team built mass spectrometry methods to profile dozens of CoA-linked forms across cells and inside mitochondria.

Finding the Door: Two Transporters With a Big Job

Once the team could see CoA species with enough clarity, the logic tightened. If synthesis happens in the cytosol, mitochondria need a gatekeeper. The study identified SLC25A42 and SLC25A16 as key transporters for bringing CoA into mitochondria. The experiment that lands with non-scientists is also the cleanest: knock out the transporter function, and mitochondrial CoA drops. That cause-and-effect turns a hunch into a mechanism.

The timeline matters because it shows why nobody “should have noticed earlier.” The paper appeared in Nature Metabolism in 2025, and Yale’s public announcement followed in March 2026, after the group had the measurement toolkit and validation experiments lined up. This wasn’t a lucky guess; it was an instrumentation-and-methods story as much as a biology story.

Vitamin B5 Isn’t “Energy”—It’s the Supply Chain Behind Energy

Pantothenic acid (vitamin B5) is essential because animals use it to build CoA through a multi-step pathway, including a rate-limiting step controlled by pantothenate kinases. CoA then participates across metabolism: it supports the Krebs cycle, fatty-acid processing, and other foundational reactions. People often talk about “mitochondrial energy” as if it’s a vibe. It’s logistics. If CoA can’t reach mitochondria, the machinery doesn’t get its critical part.

The discovery also helps explain why CoA problems show up as whole-body problems. Mitochondria sit in nearly every cell type, and tissues with high energy demand—muscle and brain especially—tend to reveal the damage first. Shen’s group highlighted interest in neuronal CoA regulation, a smart next step because the nervous system combines extreme energy needs with little tolerance for metabolic disruption. When the supply chain breaks, the brain doesn’t wait politely to complain.

What This Changes for Mitochondrial and Metabolic Disease Thinking

The most practical shift is conceptual: disease risk may come from impaired CoA import, not only impaired CoA synthesis. The transporter angle matters because it opens a different diagnostic and therapeutic map. If a patient has enough vitamin B5 intake and intact CoA synthesis enzymes, yet mitochondria still run CoA-poor, the import machinery becomes a prime suspect.

Research on rare disorders underscores why this matters. Work described in TANGO2 deficiency, for example, ties mitochondrial dysfunction to disrupted acyl-CoA transport and metabolic crises; investigators have explored high-dose vitamin B5 as part of supportive care, even while the exact mechanism remains unsettled. That uncertainty is precisely why the Yale transporter finding lands hard: it narrows the “maybe” space. Better maps don’t guarantee cures, but they stop clinicians from wandering.

The Measurement Breakthrough Hidden Inside the Headline

Most readers will remember “scientists solved a mystery,” but the deeper win is how they solved it. CoA chemistry is messy because the molecule wears different acyl “coats,” and those coats matter biologically. The Shen lab’s ability to profile 33 CoA conjugates across the cell and 23 within mitochondria created a more complete ledger of CoA reality. Better bookkeeping lets biology stop arguing about shadows and start discussing numbers.

This is also where public debates about supplements can get overheated. The study does not claim vitamin B5 megadoses are a universal fix, and common sense says it shouldn’t. If the transporter door is broken, dumping more supplies outside the building won’t automatically stock the basement. The better takeaway is precision: understand the mechanism first, then target the intervention—whether that means nutrients, drugs, or gene-informed care.

Scientists solve the mystery of a vitamin B5 molecule that powers your cells https://t.co/0XyX99eJdu

— Un1v3rs0 Z3r0 (@Un1v3rs0Z3r0) March 12, 2026

The open loop now is obvious: what happens when these transporters are subtly weakened rather than fully knocked out, and how often does that explain real patient symptoms? The study provides the missing door and the first solid map of CoA traffic into mitochondria. The next chapter—already hinted by Shen’s focus—will test how different cell types ration CoA under stress, and whether medicine can keep that courier running on time.