The Diablito poison dart frog, Oophaga sylvatica, is native to Colombia and Ecuador. Credit: Marie-Therese Fischer
Key points:
- Researchers identified a protein—alkaloid binding globulin (ABG)—that acts like a “toxin sponge” and helps poison dart frogs safely accumulate toxins.
- The way that ABG binds alkaloids has similarities to the way proteins that transport hormones in human blood bind their target.
- These results are a starting point for therapeutic strategies to treat humans poisoned with similar molecules.
A new study, published in eLife, identifies the protein that helps poison dart frogs safely accumulate toxins. These findings provide insight into potential therapeutic strategies for treating humans poisoned with similar molecules.
Tiny poison dart frogs consume large amounts of toxic alkaloids in their diets. Instead of breaking down, these toxins accumulate in frog’s skin as a defense mechanism against predators. To date, scientists did not know how poison dart frogs transport highly toxic alkaloids around their bodies without poisoning themselves.
In this study, researchers used a compound similar to the poison frog alkaloid to attract and bind proteins in blood samples from the Diablito poison frog. Their alkaloid-like compound was bioengineered to glow under fluorescent light, which allowed the team to visualize binding between the protein and the decoy.
Next, the researchers separated the proteins to determine how each interact with alkaloids in solution. They found that a protein called alkaloid binding globulin (ABG) acts like a “toxin sponge” and collects alkaloids.
“The way that ABG binds alkaloids has similarities to the way proteins that transport hormones in human blood bind their target,” explains lead author Aurora Alvarez-Buylla of Stanford University.
The similarities with human hormone-transporting proteins may be a starting point for bioengineering human proteins that can absorb toxins. These efforts would offer new options for treating certain kinds of poisonings.
“Beyond potential medical relevance, we have achieved a molecular understanding of a fundamental part of poison frog biology,” said senior author Lauren O’Connell, professor at Stanford. “This will be important for future work on the biodiversity and evolution of chemical defenses in nature.”