Scientists can be a very boring bunch when it comes to naming things. Mostly, proteins are named after their function, and end up with rather mundane names, such as Glucose Transporter 1 (GLUT1), or Cluster of Differentiation 8 (CD8). However, very occasionally, somebody creative comes along and gives a newly discovered protein a really cool name. One of these proteins is called PIKACHURIN.
As you have probably already guessed, this protein is named after the Pokémon mascot, Pikachu. It was discovered by a scientist called Shigeru Sato and his colleagues*, and was named because it “has lightning fast moves and shocking electric effects”**. But what does it do? Let’s start from the beginning.
Proteins are what we call macromolecules; they are big molecules that act as the machinery in our body. Proteins are made from amino acids. There are twenty amino acids, and depending what order they are in, the protein will be different. Some proteins will only be 100 amino acids, but others are much longer and can be hundreds of amino acids long. Our genes are responsible for causing the proteins to be made, by telling the “protein making machinery” what order to put amino acids in. When somebody tells us to eat more protein, they actually mean that we need the extra amino acids from the protein. The protein gets broken down into amino acids and made into new proteins.
Proteins are responsible for almost everything is our body. They help our cells grow, they help us metabolise our food and they even make more proteins! There are so many varieties of proteins, that we haven’t functionally characterised a huge proportion of them. We do, however, know that they are extremely important.
Pikachurin is a protein that is found in eyes. Eyes have photoreceptors, and these will move in a certain way depending on the light they receive. Photoreceptors send a signal to a synapse. The synapses are important structures that allow information to move around the brain. Synapses send signals to the brain about photoreceptor movement, and this translates the information into pictures. However, synapses can’t work alone and need the help of many different proteins. One of these proteins is Pikachurin.
Pikachurin is 1017 amino acids long*** and is found in most animals that can see. It was discovered by using a technique that allows for tissue to be scanned to see what genes and proteins are in use through testing concentrations. Another clever technique is to use fluorescent markers that bind or are bound specifically to that protein, and this was used to show that Pikachurin was found around eye synapses. The funny thing about Pikachurin is that we don’t know what its function is, we just know that it is needed in order for proper synapse function (and for some other proteins to function). Without it, the electrical impulses that send information to the brain are disrupted, and incorrect movement of synapses and proteins can lead to muscular dystrophy of the eye. It is, therefore, an important protein.
In this picture, the genes are expressed everywhere, but you can link the fluorescent protein up to a single gene/protein to see where the gene is turned on. Often, then will be in a very specific tissue, as is the case with Pikachurin.
It is normal and common to know what a protein interacts with, but not what its specific function is. The way scientists learn about gene and protein function is to look at subjects that lack the protein. Whatever is effected is probably influenced by that protein. My job is to learn about plant genes in pollen. If I want to know what a specific protein does, I will knockout the gene that makes this protein (this is quite easy to do). If the plant that no longer has this proteins grows tiny pollen grains, I will then know the protein is important in pollen growth when it is functional. This doesn’t tell me how the gene or protein helps the pollen grow, it just lets me know that the gene or protein is important in pollen growth. Pikachurin was studied in the same manner, but using mice instead of plants. It is very difficult to know how they work because we can’t just sit and watch them; they are too small.
Hopefully, as we learn more about science and improve our technology, we will be able to understand what the specific function of Pikachurin is, and how it interacts with synapses. Until then, we just have to be happy that Pokémon was so influential to the scientific community!
*Sato S, Omori Y, Katoh K, Kondo M, Kanagawa M, Miyata K, Funabiki K, Koyasu T, Kajimura N, Miyoshi T, Sawai H, Kobayashi K, Tani A, Toda T, Usukura J, Tano Y, Fujikado T, Furukawa T (August 2008). “Pikachurin, a dystroglycan ligand, is essential for photoreceptor ribbon synapse formation”. Nat. Neurosci.11 (8): 923–31.
**Levenstein, S (2008). “Lightning-Fast Vision Protein Named After Pikachu”. Inventor Spot.
*** That is a huge protein! Usually, proteins are around 300 amino acids. The ones I work with are only 131 amino acids! I bet they didn’t know how big it was when they named it, otherwise they may have named it Zapdos instead.