As people age, those who have lived a stressful lifestyle have more chance of acquiring heart arrhythmia, which can lead to potential heart failure — even if they have no genetic predisposition, researchers have found.
The research was conducted by Filip Van Petegem, a professor in the Department of Biochemistry and Molecular Biology at the University of British Columbia, with experiments taking place at the Canadian Light Source (CLS) at the University of Saskatchewan.
Stress sig nalling allows calcium, a signal for contraction, to be released into the heart muscle cells faster; as a result, the heart muscle cells can contract better and the heart can beat faster. In a stress situation, the heart protein receives a tag from another protein, which allows for more efficient delivery of the calcium.
“That’s normal stress signalling,” Van Petegem said. “But what happens is that stress signalling needs to be turned off at some point. So we’re scared, we want to run away — afterwards when we relax, that stress signal gets removed again, and we’re back to normal.”
As people age, the tags, or stress signals in the heart, can stay active for longer, which can increase the risk of heart arrhythmia.
Using X-ray diffraction at the CLS, Van Petegem created crystals from the proteins to produce 3D images, revealing a structure showing how the tag is delivered.
“We were able to see, once the tag is delivered, what changes in the three dimensional structure of that protein. And that was just not known,” he said.
Although there’s nothing alarming about some stress during the normal parts of life — stress signals are active when doing sports, as well as during emotional stress or work-related stress — problems can arise if the signals continue to stay active, he added.
“By itself, as long as it’s short-lived, that’s fine. But the bottom line is, if the stress signals stay on for too long, at some point, it can be hard to erase the stress signals.”
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