Structure of MC4R paves the way for design of new weight loss treatments.

A new paper in the journal Science reports the structure of MC4R (melanocortin 4 receptor) allowing for a 3D visualisation of how the receptor is switched on to reduce appetite and weight. This discovery is important because MC4R is the key gene for controlling weight – when it is not working people gain weight very easily. As discussed by Prof Farooqi in an accompanying Perspective article in Science, this structure will allow researchers and companies to find new ways to develop more effective weight loss medicines that activate MC4R in different ways. This will also help us to understand why certain variants in the MC4R gene stop the receptor from working and how far medicines like Setmelanotide can help people with those variants to lose weight. This breakthrough came through technological developments called cryo-EM, which freeze the receptor, stabilising it so that accurate measurements of its structure and shape can be made.