Last year, a group of scientists at the Institute for Bioengineering of Catalonia (IBEC), the Institute for Research in Biomedicine (IRB Barcelona) –based in the PCB– and the University of Barcelona (UB) announced that they had achieved photo-switchable, or light-regulated, molecules to control protein-protein interactions – key determinants in biological processes, and therefore highly promising therapeutic targets – in a remote and non-invasive manner. The discovery signified a major step towards the development of targeted, light-controlled drugs, whose effects would be limited to a specific area and time, reducing side effects.

Now, in recent experiments published in the journal Chemistry & Biology (doi: 10.1016/j.chembiol.2014.10.022), the same researchers have been using their photo-sensitive molecules to control clathrin-mediated endocytosis, a process whereby cells absorb certain substances that they need to function properly. In doing so, they’ve made a discovery that greatly expands the field of potential inhibitors, as  it questions the need for one of the previously supposed design requisites of these molecules. 

They found that the absence of a rigid, helical structure, therefore, is not a limitation when selecting candidates for photoswitchable inhibitors of nhibition protein-protein interaction (PPIs), meaning that when developing further potential inhibitors, researchers can look to the wide group of more flexible peptides for their candidates.

The most immediate therapeutic applications expected for photoswitchable inhibitors is for diseases affecting superficial tissue such as the skin, retina and external mucus membranes. In the future, photo-sensitive molecules could be used to study, for example, in vitro endocytosis in cancer cells – where this process is uncontrolled – which would allow selective inhibition of the cells’ proliferation.