There are many times when putting tarantula toxin into human cells seems like a very bad idea. At the University of California, Davis, however, it is a breakthrough idea that allows for closer examination of the electrical activity in cells, especially neurons. This opens up the field of brain study and also lends insights into conditions like muscle defects, cardiac arrhythmias, and epilepsy.
Currently, electrical activity at the cellular level isn’t very well understood. We know that electric signaling proteins switch on and off, triggering responses in the ion channels. However, we haven’t been able to witness the actual switching of these proteins without genetically modifying the subject. Changing genes to view the electrical signals is an exhausting strategy because it’s not clear which ones have what effect.
“To understand how neural systems or the heart works, we need to know which switches are activated,” says Jon Sack, assistant professor of physiology and membrane biology at UC Davis. “There are about 40 voltage-gated potassium channel genes that are basically doing the same thing, and it’s been shockingly hard to figure out which ones are doing something that’s physiologically relevant.”
This is where tarantula toxin becomes the unlikely savior of the day. The particular type that the team uses naturally binds to a type of ion channel called Kv2. The power of the electric signal from the protein is just enough to break the bond of the toxin, causing it to fall off. The result is that when Sack tags these toxins with fluorescent markers, he can tell exactly when the electric signal switches on.
(The probe turns off and on based on the electrical signal it receives. Image courtesy UC Davis)
Sack and the team believe that understanding electric signaling is vital to understanding several types of diseases. “If you have electrical signaling, you have to have a potassium channel, and when that channel goes bad, the cell doesn’t work the same anymore,” he says in a UC Davis press release.
“For example, the Kv2.1 channel that this probe binds to leads to epilepsy when it’s not functioning properly.” Other conditions caused by ion channel malfunction (dubbed channelopathies) include cardiac arrhythmias and muscle defects. The long-term goal of the team is to be able to map the neuron activity of the brain.
This project was funded by grants from the National Institutes of Health and the American Heart Association and also received support from the U.S. Department of Energy. For more funding information about UC Davis, read our free UC Davis Funding Report, available below:
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