Inside the interactome

27 May 2008

Forget gene number: it’s the number of protein interactions in an organism that appears to reflect biological complexity. What’s more, it’s hoped that in the future, comparison of protein interaction networks could help researchers to understand the different effects of similar organisms - for example, why some fungal species can be used to make bread and beer while others can cause fatal fungal infections.

In the study, researchers from Imperial College London worked with colleagues from the Max Planck Institute for Molecular Genetics in Berlin and the University of Aarhus in Denmark to devise a mathematical tool that allowed them to predict the size of an organism’s protein interaction network, or interactome.

While humans have fewer than twice as many genes as fruit flies, the human interactome is around ten times bigger than that of fruit flies, and around three times bigger than that in the nematode worm Caenorhabditis elegans.

“Understanding the human genome definitely does not go far enough to explain what makes us different from more simple creatures,” says Professor Michael Stumpf at Imperial. “Our study indicates that protein interactions could hold one of the keys to unravelling how one organism is differentiated from another.”

Stumpf MP et al. Estimating the size of the human interactome. Proc Natl Acad Sci USA 2008;105(19):6959–64.