Reveal the structure of spicy sensory organs and pain

We can now not only feel the spicy taste of the jalapeno red pepper, but also can see it in three-dimensional images thanks to researchers from Baylor College of Medicine in Houston.

Using modern equipment, the team led by Dr. Theodore G. Wensel - professor of biochemistry and molecular biology at BCM - created the first three-dimensional image of a protein that allows us to feel Pick up the spicy taste of chili.

Wensel, the author of the study, said: 'This protein, called TRPV1, not only feels spicy food, but also allows for real heat and agitation and pain related to medical conditions. other study. The protein observation method gives us the opportunity to clearly see the functional relationship between external stimuli and neurons'.

The external stimulus used in the study is the spicy flavor of chili. It has long been known that hot sensation results from the action of a chemical called capsaicin on the TRPV1 protein located on the membrane of nerve cells. TRPV1 is an ion tube, essentially a tiny hole in the cell membrane that allows chemicals like calcium to enter and exit.

Dr. Vera Moiseenkova-Bell, partner in Wensel's laboratory at BCM and author of the study, said: 'Our burning sensation or pain is regulated by TRPV1 tube. Different levels of heat are controlled by different TRP tubes. They are all related to each other but each tube is controlled in a different way. '

Wensel said the 3D image of TRPV1 revealed surprising information about its structure. It is made up of small holes attached to the cell membrane, and a 'hanging basket' in the control area extends into the inside of the cell.

We feel the hotness of chili, such as scotch bonnet peppers in the picture above, through the effects of their ingredients: capsaicin, protein, TRPV1. The protein structure, determined by electron microscopy with a ratio of 4 million times the actual size, reacts with heat and chemical stimulation by opening the tubes in the nerve cell membrane. (Photo: Jennifer Katrib)

Wensel commented: 'This is an unusual thing. There is an empty basket area but we don't know what it is for. Currently the study is investigating how this' basket 'zone controls the tubes.' The isolation of TRPV1 gives researchers a question about how the structure of the tubes is made.

Moiseenkova-Bell said: 'The image of TRPV1 tells us about TRP tubes because they are similar in structure. Pharmaceutical companies are also targeting TRP tubes to ensure that drugs bind to them effectively. With this structure we can build a linkage model, hoping in the future we can make more effective drugs that treat many different diseases. '

Researching TRP tubes is not a new idea. In the past, many scientists were able to identify activity in the cell but they could not determine which reaction was from the TRP tube. To determine the type of protein interacting with TRPV1 requires Wensel's lab to build a refined model.

Proteins must be removed from cells, refined, and regenerated on artificial membranes, from which researchers can control the activity of the tubes.

Wensel explains: 'Since calcium is involved in signaling to cells, it is necessary to monitor calcium movement to confirm protein activity. We are the first group to refine a TRPV1 tube and control what traffic comes in and out when it opens. '

The research report is published in the latest issue of the Proceedings of the National Academy of Sciences. Participants in the study included Dr. Lia Stanicu (of Purdue University), Dr. Irina Serysheva - assistant professor of biochemistry at BCM, and BCM graduate student Ben J. Tobe. The National Institutes of Health funded this study.