Specific enzymes protect cells against protein deposits

Basic researchers of the Charité Medical University in Berlin have found that cells are protected against stress, that occurs due to an inflammation and deposits of damaged proteins by a specific enzyme, the so-called immunoproteasome. Both standard proteasomes and immunoproteasomes function as recycling plant in body cells for damaged proteins.

The production of immunoproteasomes is regulated by the transmitter interferon. Altogether, this enhances the response of the immune system. However, this process is also stressful for the cells. The team of researchers shows that the main function of immunoproteasomes is the protection and the maintenance of the viability of cells under the conditions of an inflammation.

Through the release of interferons, free oxygen radicals are formed which can cause damages, particularly to newly developed proteins. Those deposit as protein lumps in the cells. As soon as enough immunoproteasomes have formed, the degradation works much better. Cells can be protected from deposits and remain viable.

In their experiments, the scientists examined the reaction of interferons in cells with immunoproteasomes and the reaction of cells that are without, due to the lack of a specific gene. They observed a continuous decrease of protein accumulations. Cells without immunoproteasomes were not able to degrade the deposits and died.
This protective effect can be demonstrated by the clinical picture of a multiple sclerosis mouse model. The lack of functional immunoproteasomes leads to an increase of disease symptoms.

Further researches of the scientist team are dedicated to disorders of the central nervous system, such as multiple sclerosis, Parkinson's disease or Alzheimer's.

Publication:
Seifert U et al., Kloetzel PM and Krüger E, Immunoproteasomes Preserve Protein Homeostasis upon Interferon-Induced Oxidative Stress, Cell (2010), DOI 10.1016/j.cell.2010.07.036

Contact:
Prof. Peter-Michael Kloetzel
Managing Director of the Institute for Biochemistry
p-m.kloetzel@charite.de


Source: Charité Medical University in Berlin