In-cell structural biology: CLIC1 structure, function and drug binding inside tumour cells

Chloride intracellular channel (CLIC) proteins consist of a family of metamorphic proteins that exist in an equilibrium between a soluble and a membrane-bound state. The alteration of CLIC function has been involved in ischaemia-reperfusion and different forms of cancer. CLIC1 has been directly linked with the proliferation of glioblastoma tumours of the brain. It can be found as a chloride channel or as soluble reduced monomers or oxidised dimers with oxidoreductase activity. CLIC1 inhibitors block both its ion channel function and oxidoreductase activity. However, it is unknown what form or forms of the protein are relevant in the context of healthy cells and glioblastoma cells and how the equilibrium between them is affected in disease.

I will study the membrane-associated and free conformations of CLIC1 by solution nuclear magnetic resonance (NMR) both in vitro and in vivo using in-cell NMR in different cell lines in combination with traditional NMR methods and fluorescence microscopy. I will identify which CLIC1 conformer is involved in disease and drug binding to understand the factors governing the equilibrium between the different CLIC1 forms and to determine the mechanism regulating such equilibrium with atomic detail.

These findings will permit further studies to develop more specific therapeutic drugs for glioblastoma.