German researchers have shown a new mechanism via which cells defend themselves against stress. Dr. Kathrin Thedieck and Birgit Holzwarth from the Institute of Biology III and the Cluster of Excellence BIOSS Centre for Biological Signalling Studies of the University of Freiburg have discovered that Astrin, a rarely investigated component of many cells, plays an important part in this process. The scientists demonstrated the stress function of Astrin, which was previously mainly known for its role in cell division, and published their findings in the renowned scientific journal Cell. Astrin maybe an important drug target, as tumor cells avoid cell death due to high Astrin levels.
Free radicals, much like combustion exhaust gases, arise from external sources or cellular metabolism and cause stress in the body cells. Cellular stress is thought to contribute to the development of age-related diseases including cancer, neurodegenerative diseases, or metabolic disorders. “The protein complex mTORC1 (mammalian target of rapamycin) plays a key role in balancing growth and degradation,” says Dr. Thedieck, junior group leader from Freiburg. Nutrients activate mTORC1, allowing the cell to grow. In addition, mTORC1 helps the cell to cope with moderate stress. However, as mTORC1 activity becomes too high, the cell initiates programmed cell death. “Upon increasing stress, we observe so-called stress granules which prevent mTORC1 hyperactivation and, hence immediate cell death under transient stresses. Until now, however, the molecular mechanism governing this process was unknown,” says Thedieck.
Read more at: Phys.org