Our research is in the area of immunology, molecular cell biology, and biochemistry, specifically on the intracellular transport of membrane proteins of the immune system, and its regulation.

Our favorite model system are major histocompatibility complex (MHC) class I molecules, which are present on all nucleated cells. They play a central role in the mammalian immune defence against viruses, intracellular bacteria, and cancer, since they carry fragments of many intracellular proteins to the surface of the cell, where they can be surveyed by cytotoxic T lymphocytes (CTL). If the CTL find that unusual proteins (for example, non-self) are produced in the cell, they induce it to undergo apoptosis. This way, the production sites of viruses are eliminated.

The intracellular transport of MHC class I molecules is very interesting, since it is regulated by the presence of the bound peptide fragment. Only with a bound peptide, class I molecules travel to the cell surface. We are asking what changes are brought about in the structure of the class I molecule by the peptide, how these changes are read out by the cell, and how the decision is made to localize the class I molecule either inside the cell, or on its surface.

A second project area concerns the introduction of soluble substances, for example peptides or second messengers, into cells, either to manipulate their behavior or to make measurements. We work with biophysicists who design micrometer-sized capsules that can be opened inside the cells. This system is also used to study MHC class I molecules.

Our main methods are laser confocal fluorescence microscopy, cell biological protein transport experiments (pulse chases), biochemical in vitro assays of intracellular transport processes, and biophysical assays with purified proteins.