BIOPRO: Dr. Schulte, how important are membrane proteins for the pharmaceutical and biotechnology sectors?

Schulte: Until a couple of years ago, around two thirds of all drugs targeted membrane proteins, including receptors that transfer external signals into cells or ion channels that control the flow of current to nerve cells. Substances that target such membrane proteins have the potential to alter the behaviour of cancer cells or modulate the transfer of information between neurons. Since then, there has been major progress in the technologies that overcome membrane barriers, in the sense that a growing number of pharmaceutically active substances is now able to directly influence intracellular proteins, including enzymes or modulators of signalling networks. This is hugely advantageous because the characterisation of membrane proteins is far more difficult than the characterisation of proteins found in the aqueous environment inside cells.

BIOPRO: Does this mean that membrane proteins are no longer interesting targets for the pharmaceutical industry?

BIOPRO: In which direction is research on membrane proteins going?

Schulte: We now know that membrane proteins do not exert their function as individual proteins. They are frequently associated with other membrane proteins or with proteins in the cell's interior in the form of complexes or networks. If one seeks to understand and modulate their function, it is necessary to decipher these complexes and networks. In cooperation with the research group led by Prof. Dr. Bernd Fakler at the Institute of Physiology at the University of Freiburg, we have for example investigated a family of calcium channels in neurons. These channels interact with a broad range of proteins, which in turn are associated with other proteins; we have identified around two hundred proteins in this network. We also used our methods to determine the quantity of the individual proteins in order to find out which interactions are particularly stable or frequent, and in order to identify protein complexes in these networks. In principle, it is difficult to automate such interaction studies with biological tissue, therefore we do not offer high-throughput experiments. Our customers benefit from our support in solving very complicated issues, where we need to look closely into all the aspects and which require the highest technical quality.

BIOPRO: How has Logopharm developed over the last few years?