Researchers at the Ted Rogers Centre for Heart Research have discovered a unique compilation of proteins which provide vital information into the phenomenon of contractility.

Researchers claim that these membrane proteins could play a significant role in normal heart functions, as well as in heart failure and heartbeat anomalies (arrhythmias). Moreover, scientists could get important insights into how heart disease alters signal pathways within the heart.

The study, led by Professor Anthony Gramolini and Professor Thomas Kislinger, from University of Toronto’s Department of Physiology and Medical Biophysics respectively, used hi-tech methods to uncover over 500 membrane proteins that reside on the surface of cardiac cells.

Novel Proteins That Make The Heart Go

The team’s focus was a protein called Tmem65, the transmembrane protein 65. By analyzing human stem cells and zebrafish via cell imaging and biochemical methods, they discovered that the protein was involved in electrical and communication processes, scientifically known as electrical coupling and calcium signaling.

Researchers demonstrated how Tmem65 regulated connection points between subsequent contractile cardiac cells, hence contributing to normal heart contractility. Removing the protein resulted in grave consequences. Furthermore, the protein was identified as the first significant tool for stem-cell scientists to monitor the growth of cells in the bottom two chambers of the hearts (ventricles).

“Theoretically, these proteins are suitable targets for interventions and basic studies”, explained Gramolini. “Our study focused on Tmem65, but there are 555 other proteins that we identified were present among many species, having been conserved throughout evolution in the heart’s membrane-enriched contractile cells”.

Future Prospects

The study, published in Nature Communications, provides novel insights into the basic functioning of a healthy human and mouse heart, providing scientists with substantial information regarding the mechanisms involved in cardiac anomalies.

Gramolini stated that the findings were essential for comprehending basic cardiac biology, and will hopefully open new avenues for cardiac health and disease in laboratories.

“We need to figure out exactly what all of these molecules are doing. These molecules haven’t been studied before, but must somehow be associated with heart function. If a protein remains conserved in evolution, it must generally have a major function – this prospect is very exciting.”