Research News
Crystalline calcium pump specimen extracted from thale cress. Photo: Henning Tidow/University of Aarhus
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Calcium Pump Booster
Using the X-ray source DORIS at the Deutsches Elektronen-Synchrotron DESY, a research team has discovered that, in the event of high levels of calcium, the calcium pumps in our body cells switch on a booster. The results have been published in the esteemed journal "Nature". Calcium is an important control signal for numerous processes within the organism. The decisive factor is the difference in its levels of concentration between the cells' interior and their environment, a difference that is regulated by calcium pumps. Using the method of X-ray crystallography on crystallised complexes of calcium pumps, the researchers now have identified two binding sites for the protein Calmodulin.
When calcium binds to Calmodulin, this in turn can bind to the calcium pump and thereby switch it on. The pump is controlled by three instances: It is switched off, when no Calmodulin is bound. When one binding site is occupied, the pump operates at a medium speed. In the event of high calcium levels, both sites are occupied and the pump switches to the newly discovered booster speed. Bioinformatics analyses now have revealed that all cells containing a nucleus – from a single cell organism to human beings – feature this booster switch.
