Neurons – Neurons in our body are filled with tiny pores that allow essential molecules to pass in and out of our cells. Neurons need these channels to send signals that allow us to move, think, and perceive the world around us. Now, structural biologists at Cold Spring Harbor Laboratory (CSHL) have captured never-before-seen images of one of the largest pores in human neurons. It is called calcium homeostasis modulator protein 1 or CALHM1 for short.
Previous studies have shown mutations Cahlm1 Genes are a risk factor for Alzheimer’s disease. CSHL’s new research reveals, for the first time, how the channel works in humans and how it can be disrupted.
CSHL Professor Hiro Furukawa and postdoc Johanna Sirjanen have been studying CALHM1 for several years. It appears to be involved in a wide array of physiological processes. On our tongue, CALHM1 detects tastes like sweet, sour or umami. In our brains, CALHM1 may play a role in controlling the buildup of a plaque-forming protein associated with Alzheimer’s.
Furukawa, Sirjanen, and colleagues used a method Cryo-electron microscopy to generate detailed, three-dimensional images of the human CALHM1 channel. The images show how eight copies of the CALHM1 protein come together to form a circular channel. Each protein has a flexible arm that reaches into the pore and controls how it opens and closes. Sirjanan likens the arms to “octopus tentacles.”
The team also found that fatty molecules called phospholipids are critical for stabilizing and regulating the eight-part channel. Eggs, whole grains, lean meats and seafood Contains all these essential fats. Additionally, Furukawa’s lab showed how the chemical the researchers use to block CALHM1 is deposited in the channel. That knowledge could be useful if one day researchers aim to develop a drug that targets CALHM1. Sirjanan says:
“If you think along the lines of, ‘Can we manipulate taste perception or influence this protein?’ Now we know one of the places where you can inhibit protein activity.
Sirjanen notes that the human CALHM1 channel looks similar to her and Furukawa studied in chickens In 2020. Determining the structure of the human protein proved technically more challenging. But the researchers agree that it is essential to understand the channel’s role in human health.
“There are many unanswered questions surrounding CALHM1,” says Furukawa. For example, how does the energy-carrying molecule ATP escape from cells through this channel? Does this cause the body’s inflammatory response? “Our research team will continue to unravel this important molecular mechanism to better understand the function of the CALHM1 channel.”