Researchers from the University of Cambridge have discovered a novel genetic cause of severe obesity which, although relatively rare, demonstrates for the first time that genes can reduce basal metabolic rate (how the body burns calories). Previous studies demonstrated that when the gene KSR2 (Kinase Suppressor of Ras 2) was deleted in mice, the animals became severely obese.
As a result of this research, Professor Sadaf Farooqi from the University of Cambridge’s Wellcome Trust-MRC Institute of Metabolic Science explored whether KSR2 mutations might also lead to obesity in humans. In collaboration with Dr Ines Barroso’s team at the Wellcome Trust Sanger Institute, the researchers sequenced the DNA from over 2,000 severely obese patients and identified multiple mutations in the KSR2 gene. The research was published in the journal Cell.
KSR2 belongs to a group of proteins called scaffolding proteins which play a critical role in ensuring that signals from hormones such as insulin are correctly processed by cells in the body to regulate how cells grow, divide and use energy. To investigate how KSR2 mutations might lead to obesity, Professor Farooqi’s team performed a series of experiments which showed that many of the mutations disrupt these cellular signals and, importantly, reduce the ability of cells to use glucose and fatty acids.
Changes in diet and levels of physical activity underlie the recent increase in obesity in the UK and worldwide. However, there is a lot of variation in how much weight people gain. This variation between people is largely influenced by genetic factors, and many of the genes involved act in the brain. The discovery of a new obesity gene, KSR2, adds another level of complexity to the body’s mechanisms for regulating weight. The Cambridge team is continuing to study the genetic factors influencing obesity, findings which they hope to translate into beneficial therapies in the future.
Professor Farooqi’s research was funded by the Wellcome Trust.
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