Mapping insulin's path through the human body

Researchers from the University of Sydney have published a diagram which charts, in unprecedented detail, the insulin/IGF1 signalling pathway (ISP) - a complex network of molecular interactions triggered by insulin which plays an essential role in long-term health, obesity and diseases such as diabetes.

“When we eat glucose, it comes into the bloodstream and triggers insulin secretion,” said Professor David James. “Insulin then travels via the blood and binds to receptor molecules, principally on muscle, fat or liver tissue.

“The great complexity begins when the insulin binds to that tissue, which initiates a very convoluted series of many thousands of molecular events.

“These events don’t just happen all at once - they can come on very quickly or very slowly, some go up and some go down, some happen in the nucleus, some happen in other parts of the cell.”

Now, said Professor James, the team has been able to display all of the main events in a simple image. Drawing on research by Professor James, the map was created by data visualisation specialist Dr Séan O’Donoghue and also included contributions from molecular biologists, bioinformaticians, data visualisation experts and a graphic designer.

Dubbed ‘Minardo’, the diagram was inspired by a map designed by French civil engineer Charles Minard and commissioned by Napoleon Bonaparte to chart his Russian campaign of 1812. Minard’s map is famous for charting six types of data in one image: the number of Napoleon’s troops, distance, temperature, latitude and longitude, direction of travel and location relative to specific dates.

Similarly, Dr O’Donoghue’s design condenses multiple dimensions of information, including time, cellular topology and a range of specific biochemical processes such as fatty acid secretion, inhibition of lipolysis and the initiation of glycolysis and protein synthesis. An interactive online version allows users to see moving parts and find additional information by hovering over the displayed events.

It is hoped Minardo will help explain ISP to students and scientists in other areas, improving understanding of the vitally important but poorly understood process. Professor James said the map will be “very useful for other scientists working in other areas such as cancer, who may be able to use the same concept for their branch of science”.